diff mbox

[4/5] drm/intel/dp: Try harder to get bpc of a DP sink if EDID doesn't tell.

Message ID 1467799548-13229-5-git-send-email-mario.kleiner.de@gmail.com (mailing list archive)
State New, archived
Headers show

Commit Message

Mario Kleiner July 6, 2016, 10:05 a.m. UTC
For DP sinks which don't expose color depth via EDID, use
the drm_dp_sink_bpc() helper to derive the bpc of the sink.

This should handle DP native sinks with the "Assume 6 bpc if EDID
doesn't tell us" as mandated by DP spec. It gives more accurate
values for DP->legacy converters for HDMI, DVI and VGA.

Signed-off-by: Mario Kleiner <mario.kleiner.de@gmail.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Jani Nikula <jani.nikula@intel.com>
---
 drivers/gpu/drm/i915/intel_display.c | 26 +++++++++++++++++++++-----
 drivers/gpu/drm/i915/intel_dp.c      |  7 +++++++
 drivers/gpu/drm/i915/intel_drv.h     |  1 +
 3 files changed, 29 insertions(+), 5 deletions(-)

Comments

Dave Airlie Aug. 3, 2016, 3:07 a.m. UTC | #1
On 6 July 2016 at 20:05, Mario Kleiner <mario.kleiner.de@gmail.com> wrote:
> For DP sinks which don't expose color depth via EDID, use
> the drm_dp_sink_bpc() helper to derive the bpc of the sink.
>
> This should handle DP native sinks with the "Assume 6 bpc if EDID
> doesn't tell us" as mandated by DP spec. It gives more accurate
> values for DP->legacy converters for HDMI, DVI and VGA.

Haswell says no.

ug 03 12:58:46 tyrion-bne-redhat-com kernel: fbcon: inteldrmfb (fb0)
is primary device
Aug 03 12:58:46 tyrion-bne-redhat-com kernel: BUG: unable to handle
kernel NULL pointer dereference at 000000000000011b
Aug 03 12:58:46 tyrion-bne-redhat-com kernel: IP: [<ffffffffa00e6cf5>]
drm_dp_sink_bpc+0x5/0xb0 [drm_kms_helper]
Aug 03 12:58:46 tyrion-bne-redhat-com kernel: PGD 0
Aug 03 12:58:46 tyrion-bne-redhat-com kernel: Oops: 0000 [#1] SMP
Aug 03 12:58:46 tyrion-bne-redhat-com kernel: Modules linked in: i915
ccm xt_CHECKSUM ipt_MASQUERADE nf_nat_masquerade_ipv4 tun
ip6t_rpfilter ip6t_
Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  videobuf2_core
snd_hda_codec videodev mei_me mei snd_hwdep snd_seq snd_hda_core
rtsx_pci media i2c_i
Aug 03 12:58:46 tyrion-bne-redhat-com kernel: CPU: 1 PID: 752 Comm:
kworker/1:3 Not tainted 4.7.0+ #12
Aug 03 12:58:46 tyrion-bne-redhat-com kernel: Hardware name: LENOVO
20ARS25701/20ARS25701, BIOS GJET72WW (2.22 ) 02/21/2014
Aug 03 12:58:46 tyrion-bne-redhat-com kernel: Workqueue: events_long
drm_dp_mst_link_probe_work [drm_kms_helper]
Aug 03 12:58:46 tyrion-bne-redhat-com kernel: task: ffff880308583a80
task.stack: ffff880309f20000
Aug 03 12:58:46 tyrion-bne-redhat-com kernel: RIP:
0010:[<ffffffffa00e6cf5>]  [<ffffffffa00e6cf5>]
drm_dp_sink_bpc+0x5/0xb0 [drm_kms_helper]
Aug 03 12:58:46 tyrion-bne-redhat-com kernel: RSP:
0018:ffff880309f23b48  EFLAGS: 00010202
Aug 03 12:58:46 tyrion-bne-redhat-com kernel: RAX: 000000000000000a
RBX: 0000000000000006 RCX: 0000000000000000
Aug 03 12:58:46 tyrion-bne-redhat-com kernel: RDX: 0000000000000000
RSI: 0000000000000127 RDI: 0000000000000116
Aug 03 12:58:46 tyrion-bne-redhat-com kernel: RBP: ffff880309f23b50
R08: ffff880309734800 R09: 0000000000000024
Aug 03 12:58:46 tyrion-bne-redhat-com kernel: R10: 0000000000000000
R11: 0000000000000000 R12: ffff880309737800
Aug 03 12:58:46 tyrion-bne-redhat-com kernel: R13: ffff88030a334000
R14: ffff880309737000 R15: ffff880309737800
Aug 03 12:58:46 tyrion-bne-redhat-com kernel: FS:
0000000000000000(0000) GS:ffff88031e240000(0000)
knlGS:0000000000000000
Aug 03 12:58:46 tyrion-bne-redhat-com kernel: CS:  0010 DS: 0000 ES:
0000 CR0: 0000000080050033
Aug 03 12:58:46 tyrion-bne-redhat-com kernel: CR2: 000000000000011b
CR3: 0000000001c06000 CR4: 00000000001406e0
Aug 03 12:58:46 tyrion-bne-redhat-com kernel: Stack:
Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  ffffffffa09d4295
ffff880309f23bd8 ffffffffa09a7c1f ffffffff8122544d
Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  ffff880306660258
ffff880306660000 0000000009737800 ffff88030a331000
Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  0100880300000024
ffff880309f23bb8 ffffffff00000024 ffff880309737800
Aug 03 12:58:46 tyrion-bne-redhat-com kernel: Call Trace:
Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffffa09d4295>] ?
intel_dp_sink_bpc+0x25/0x30 [i915]
Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffffa09a7c1f>]
intel_atomic_check+0xacf/0x1250 [i915]
Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffff8122544d>] ?
__kmalloc_track_caller+0x12d/0x210
Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffffa0097ea7>]
drm_atomic_check_only+0x187/0x610 [drm]
Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffffa0098857>] ?
drm_atomic_add_affected_connectors+0x27/0xf0 [drm]
Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffffa0098347>]
drm_atomic_commit+0x17/0x60 [drm]
Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffffa00f4e0c>]
restore_fbdev_mode+0x14c/0x260 [drm_kms_helper]
Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffffa00f6a23>]
drm_fb_helper_restore_fbdev_mode_unlocked+0x33/0x80 [drm_kms_helper]
Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffffa00f6a9d>]
drm_fb_helper_set_par+0x2d/0x50 [drm_kms_helper]
Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffffa00f69b8>]
drm_fb_helper_hotplug_event+0x148/0x180 [drm_kms_helper]
Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffffa09c238a>]
intel_fbdev_output_poll_changed+0x1a/0x20 [i915]
Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffffa00e79c7>]
drm_kms_helper_hotplug_event+0x27/0x30 [drm_kms_helper]
Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffffa09cafa5>]
intel_dp_mst_hotplug+0x15/0x20 [i915]
Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffffa00ee31a>]
drm_dp_send_link_address+0x19a/0x220 [drm_kms_helper]
Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffff810df553>] ?
put_prev_entity+0x33/0x410
Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffff8111280b>] ?
add_timer_on+0xdb/0x1b0
Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffff8102c766>] ?
__switch_to+0x2b6/0x600
Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffff810e361e>] ?
pick_next_task_fair+0x10e/0x4d0
Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffffa00ee44d>]
drm_dp_check_and_send_link_address+0xad/0xc0 [drm_kms_helper]
Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffffa00ee4b7>]
drm_dp_mst_link_probe_work+0x57/0xb0 [drm_kms_helper]
Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffff810c086f>]
process_one_work+0x15f/0x410
Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffff810c0b6e>]
worker_thread+0x4e/0x480
Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffff810c0b20>] ?
process_one_work+0x410/0x410
Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffff810c0b20>] ?
process_one_work+0x410/0x410
Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffff810c64c8>]
kthread+0xd8/0xf0
Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffff817d527f>]
ret_from_fork+0x1f/0x40
Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffff810c63f0>] ?
kthread_worker_fn+0x170/0x170
Aug 03 12:58:46 tyrion-bne-redhat-com kernel: Code: b8 b0 1e 04 00 48
89 e5 74 11 40 80 ff 14 ba d0 78 02 00 b8 60 3d 08 00 0f 45 c2 5d c3
66 0f 1f
Aug 03 12:58:46 tyrion-bne-redhat-com kernel: RIP
[<ffffffffa00e6cf5>] drm_dp_sink_bpc+0x5/0xb0 [drm_kms_helper]
Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  RSP <ffff880309f23b48>
Aug 03 12:58:46 tyrion-bne-redhat-com kernel: CR2: 000000000000011b
Aug 03 12:58:46 tyrion-bne-redhat-com kernel: ---[ end trace
d3270996301ba013 ]---

Possibly MST related.

Dave.
Daniel Vetter Aug. 3, 2016, 6:09 a.m. UTC | #2
On Wed, Aug 03, 2016 at 01:07:12PM +1000, Dave Airlie wrote:
> On 6 July 2016 at 20:05, Mario Kleiner <mario.kleiner.de@gmail.com> wrote:
> > For DP sinks which don't expose color depth via EDID, use
> > the drm_dp_sink_bpc() helper to derive the bpc of the sink.
> >
> > This should handle DP native sinks with the "Assume 6 bpc if EDID
> > doesn't tell us" as mandated by DP spec. It gives more accurate
> > values for DP->legacy converters for HDMI, DVI and VGA.
> 
> Haswell says no.

Yup indeed, sorry for missing that. Tomeu and Mika Kahola are working on
some fancy new dp helper to probe all that, and as part of that suitably
fill out connector->display_info, too. That would allow both the
inversion, and the dpcd transaction from within atomic_check (which is
kinda not that cool either).
-Daniel

> 
> ug 03 12:58:46 tyrion-bne-redhat-com kernel: fbcon: inteldrmfb (fb0)
> is primary device
> Aug 03 12:58:46 tyrion-bne-redhat-com kernel: BUG: unable to handle
> kernel NULL pointer dereference at 000000000000011b
> Aug 03 12:58:46 tyrion-bne-redhat-com kernel: IP: [<ffffffffa00e6cf5>]
> drm_dp_sink_bpc+0x5/0xb0 [drm_kms_helper]
> Aug 03 12:58:46 tyrion-bne-redhat-com kernel: PGD 0
> Aug 03 12:58:46 tyrion-bne-redhat-com kernel: Oops: 0000 [#1] SMP
> Aug 03 12:58:46 tyrion-bne-redhat-com kernel: Modules linked in: i915
> ccm xt_CHECKSUM ipt_MASQUERADE nf_nat_masquerade_ipv4 tun
> ip6t_rpfilter ip6t_
> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  videobuf2_core
> snd_hda_codec videodev mei_me mei snd_hwdep snd_seq snd_hda_core
> rtsx_pci media i2c_i
> Aug 03 12:58:46 tyrion-bne-redhat-com kernel: CPU: 1 PID: 752 Comm:
> kworker/1:3 Not tainted 4.7.0+ #12
> Aug 03 12:58:46 tyrion-bne-redhat-com kernel: Hardware name: LENOVO
> 20ARS25701/20ARS25701, BIOS GJET72WW (2.22 ) 02/21/2014
> Aug 03 12:58:46 tyrion-bne-redhat-com kernel: Workqueue: events_long
> drm_dp_mst_link_probe_work [drm_kms_helper]
> Aug 03 12:58:46 tyrion-bne-redhat-com kernel: task: ffff880308583a80
> task.stack: ffff880309f20000
> Aug 03 12:58:46 tyrion-bne-redhat-com kernel: RIP:
> 0010:[<ffffffffa00e6cf5>]  [<ffffffffa00e6cf5>]
> drm_dp_sink_bpc+0x5/0xb0 [drm_kms_helper]
> Aug 03 12:58:46 tyrion-bne-redhat-com kernel: RSP:
> 0018:ffff880309f23b48  EFLAGS: 00010202
> Aug 03 12:58:46 tyrion-bne-redhat-com kernel: RAX: 000000000000000a
> RBX: 0000000000000006 RCX: 0000000000000000
> Aug 03 12:58:46 tyrion-bne-redhat-com kernel: RDX: 0000000000000000
> RSI: 0000000000000127 RDI: 0000000000000116
> Aug 03 12:58:46 tyrion-bne-redhat-com kernel: RBP: ffff880309f23b50
> R08: ffff880309734800 R09: 0000000000000024
> Aug 03 12:58:46 tyrion-bne-redhat-com kernel: R10: 0000000000000000
> R11: 0000000000000000 R12: ffff880309737800
> Aug 03 12:58:46 tyrion-bne-redhat-com kernel: R13: ffff88030a334000
> R14: ffff880309737000 R15: ffff880309737800
> Aug 03 12:58:46 tyrion-bne-redhat-com kernel: FS:
> 0000000000000000(0000) GS:ffff88031e240000(0000)
> knlGS:0000000000000000
> Aug 03 12:58:46 tyrion-bne-redhat-com kernel: CS:  0010 DS: 0000 ES:
> 0000 CR0: 0000000080050033
> Aug 03 12:58:46 tyrion-bne-redhat-com kernel: CR2: 000000000000011b
> CR3: 0000000001c06000 CR4: 00000000001406e0
> Aug 03 12:58:46 tyrion-bne-redhat-com kernel: Stack:
> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  ffffffffa09d4295
> ffff880309f23bd8 ffffffffa09a7c1f ffffffff8122544d
> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  ffff880306660258
> ffff880306660000 0000000009737800 ffff88030a331000
> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  0100880300000024
> ffff880309f23bb8 ffffffff00000024 ffff880309737800
> Aug 03 12:58:46 tyrion-bne-redhat-com kernel: Call Trace:
> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffffa09d4295>] ?
> intel_dp_sink_bpc+0x25/0x30 [i915]
> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffffa09a7c1f>]
> intel_atomic_check+0xacf/0x1250 [i915]
> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffff8122544d>] ?
> __kmalloc_track_caller+0x12d/0x210
> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffffa0097ea7>]
> drm_atomic_check_only+0x187/0x610 [drm]
> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffffa0098857>] ?
> drm_atomic_add_affected_connectors+0x27/0xf0 [drm]
> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffffa0098347>]
> drm_atomic_commit+0x17/0x60 [drm]
> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffffa00f4e0c>]
> restore_fbdev_mode+0x14c/0x260 [drm_kms_helper]
> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffffa00f6a23>]
> drm_fb_helper_restore_fbdev_mode_unlocked+0x33/0x80 [drm_kms_helper]
> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffffa00f6a9d>]
> drm_fb_helper_set_par+0x2d/0x50 [drm_kms_helper]
> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffffa00f69b8>]
> drm_fb_helper_hotplug_event+0x148/0x180 [drm_kms_helper]
> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffffa09c238a>]
> intel_fbdev_output_poll_changed+0x1a/0x20 [i915]
> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffffa00e79c7>]
> drm_kms_helper_hotplug_event+0x27/0x30 [drm_kms_helper]
> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffffa09cafa5>]
> intel_dp_mst_hotplug+0x15/0x20 [i915]
> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffffa00ee31a>]
> drm_dp_send_link_address+0x19a/0x220 [drm_kms_helper]
> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffff810df553>] ?
> put_prev_entity+0x33/0x410
> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffff8111280b>] ?
> add_timer_on+0xdb/0x1b0
> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffff8102c766>] ?
> __switch_to+0x2b6/0x600
> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffff810e361e>] ?
> pick_next_task_fair+0x10e/0x4d0
> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffffa00ee44d>]
> drm_dp_check_and_send_link_address+0xad/0xc0 [drm_kms_helper]
> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffffa00ee4b7>]
> drm_dp_mst_link_probe_work+0x57/0xb0 [drm_kms_helper]
> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffff810c086f>]
> process_one_work+0x15f/0x410
> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffff810c0b6e>]
> worker_thread+0x4e/0x480
> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffff810c0b20>] ?
> process_one_work+0x410/0x410
> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffff810c0b20>] ?
> process_one_work+0x410/0x410
> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffff810c64c8>]
> kthread+0xd8/0xf0
> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffff817d527f>]
> ret_from_fork+0x1f/0x40
> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffff810c63f0>] ?
> kthread_worker_fn+0x170/0x170
> Aug 03 12:58:46 tyrion-bne-redhat-com kernel: Code: b8 b0 1e 04 00 48
> 89 e5 74 11 40 80 ff 14 ba d0 78 02 00 b8 60 3d 08 00 0f 45 c2 5d c3
> 66 0f 1f
> Aug 03 12:58:46 tyrion-bne-redhat-com kernel: RIP
> [<ffffffffa00e6cf5>] drm_dp_sink_bpc+0x5/0xb0 [drm_kms_helper]
> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  RSP <ffff880309f23b48>
> Aug 03 12:58:46 tyrion-bne-redhat-com kernel: CR2: 000000000000011b
> Aug 03 12:58:46 tyrion-bne-redhat-com kernel: ---[ end trace
> d3270996301ba013 ]---
> 
> Possibly MST related.
> 
> Dave.
Mario Kleiner Aug. 3, 2016, 12:03 p.m. UTC | #3
On 08/03/2016 08:09 AM, Daniel Vetter wrote:
> On Wed, Aug 03, 2016 at 01:07:12PM +1000, Dave Airlie wrote:
>> On 6 July 2016 at 20:05, Mario Kleiner <mario.kleiner.de@gmail.com> wrote:
>>> For DP sinks which don't expose color depth via EDID, use
>>> the drm_dp_sink_bpc() helper to derive the bpc of the sink.
>>>
>>> This should handle DP native sinks with the "Assume 6 bpc if EDID
>>> doesn't tell us" as mandated by DP spec. It gives more accurate
>>> values for DP->legacy converters for HDMI, DVI and VGA.
>>
>> Haswell says no.
>
> Yup indeed, sorry for missing that. Tomeu and Mika Kahola are working on
> some fancy new dp helper to probe all that, and as part of that suitably
> fill out connector->display_info, too. That would allow both the
> inversion, and the dpcd transaction from within atomic_check (which is
> kinda not that cool either).
> -Daniel
>

Ups, sorry. They were only successfully tested with Ironlake and 
Ivybridge, non-MST, all the Intel hw i have here.

Anyway, patches 1+2 and 5 are independent of those and will fix existing 
bugs and regressions in stable kernels. Patch 1 fixes what the commit 
reverted in patch 2 was fixing. Patch 2 fixes the DP->legacy regressions 
which affect my users, patch 5 adds robustness for DVI sinks in general, 
making full use of EDID 1.3 info.

Maybe the logic in patch 3 can be somehow useful for Tomeu and Mika, as 
it was tested with different dp -> xx adapters. Happy to review or test 
once they have stuff ready.

thanks,
-mario

>>
>> ug 03 12:58:46 tyrion-bne-redhat-com kernel: fbcon: inteldrmfb (fb0)
>> is primary device
>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel: BUG: unable to handle
>> kernel NULL pointer dereference at 000000000000011b
>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel: IP: [<ffffffffa00e6cf5>]
>> drm_dp_sink_bpc+0x5/0xb0 [drm_kms_helper]
>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel: PGD 0
>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel: Oops: 0000 [#1] SMP
>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel: Modules linked in: i915
>> ccm xt_CHECKSUM ipt_MASQUERADE nf_nat_masquerade_ipv4 tun
>> ip6t_rpfilter ip6t_
>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  videobuf2_core
>> snd_hda_codec videodev mei_me mei snd_hwdep snd_seq snd_hda_core
>> rtsx_pci media i2c_i
>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel: CPU: 1 PID: 752 Comm:
>> kworker/1:3 Not tainted 4.7.0+ #12
>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel: Hardware name: LENOVO
>> 20ARS25701/20ARS25701, BIOS GJET72WW (2.22 ) 02/21/2014
>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel: Workqueue: events_long
>> drm_dp_mst_link_probe_work [drm_kms_helper]
>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel: task: ffff880308583a80
>> task.stack: ffff880309f20000
>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel: RIP:
>> 0010:[<ffffffffa00e6cf5>]  [<ffffffffa00e6cf5>]
>> drm_dp_sink_bpc+0x5/0xb0 [drm_kms_helper]
>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel: RSP:
>> 0018:ffff880309f23b48  EFLAGS: 00010202
>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel: RAX: 000000000000000a
>> RBX: 0000000000000006 RCX: 0000000000000000
>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel: RDX: 0000000000000000
>> RSI: 0000000000000127 RDI: 0000000000000116
>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel: RBP: ffff880309f23b50
>> R08: ffff880309734800 R09: 0000000000000024
>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel: R10: 0000000000000000
>> R11: 0000000000000000 R12: ffff880309737800
>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel: R13: ffff88030a334000
>> R14: ffff880309737000 R15: ffff880309737800
>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel: FS:
>> 0000000000000000(0000) GS:ffff88031e240000(0000)
>> knlGS:0000000000000000
>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel: CS:  0010 DS: 0000 ES:
>> 0000 CR0: 0000000080050033
>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel: CR2: 000000000000011b
>> CR3: 0000000001c06000 CR4: 00000000001406e0
>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel: Stack:
>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  ffffffffa09d4295
>> ffff880309f23bd8 ffffffffa09a7c1f ffffffff8122544d
>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  ffff880306660258
>> ffff880306660000 0000000009737800 ffff88030a331000
>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  0100880300000024
>> ffff880309f23bb8 ffffffff00000024 ffff880309737800
>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel: Call Trace:
>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffffa09d4295>] ?
>> intel_dp_sink_bpc+0x25/0x30 [i915]
>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffffa09a7c1f>]
>> intel_atomic_check+0xacf/0x1250 [i915]
>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffff8122544d>] ?
>> __kmalloc_track_caller+0x12d/0x210
>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffffa0097ea7>]
>> drm_atomic_check_only+0x187/0x610 [drm]
>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffffa0098857>] ?
>> drm_atomic_add_affected_connectors+0x27/0xf0 [drm]
>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffffa0098347>]
>> drm_atomic_commit+0x17/0x60 [drm]
>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffffa00f4e0c>]
>> restore_fbdev_mode+0x14c/0x260 [drm_kms_helper]
>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffffa00f6a23>]
>> drm_fb_helper_restore_fbdev_mode_unlocked+0x33/0x80 [drm_kms_helper]
>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffffa00f6a9d>]
>> drm_fb_helper_set_par+0x2d/0x50 [drm_kms_helper]
>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffffa00f69b8>]
>> drm_fb_helper_hotplug_event+0x148/0x180 [drm_kms_helper]
>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffffa09c238a>]
>> intel_fbdev_output_poll_changed+0x1a/0x20 [i915]
>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffffa00e79c7>]
>> drm_kms_helper_hotplug_event+0x27/0x30 [drm_kms_helper]
>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffffa09cafa5>]
>> intel_dp_mst_hotplug+0x15/0x20 [i915]
>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffffa00ee31a>]
>> drm_dp_send_link_address+0x19a/0x220 [drm_kms_helper]
>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffff810df553>] ?
>> put_prev_entity+0x33/0x410
>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffff8111280b>] ?
>> add_timer_on+0xdb/0x1b0
>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffff8102c766>] ?
>> __switch_to+0x2b6/0x600
>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffff810e361e>] ?
>> pick_next_task_fair+0x10e/0x4d0
>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffffa00ee44d>]
>> drm_dp_check_and_send_link_address+0xad/0xc0 [drm_kms_helper]
>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffffa00ee4b7>]
>> drm_dp_mst_link_probe_work+0x57/0xb0 [drm_kms_helper]
>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffff810c086f>]
>> process_one_work+0x15f/0x410
>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffff810c0b6e>]
>> worker_thread+0x4e/0x480
>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffff810c0b20>] ?
>> process_one_work+0x410/0x410
>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffff810c0b20>] ?
>> process_one_work+0x410/0x410
>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffff810c64c8>]
>> kthread+0xd8/0xf0
>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffff817d527f>]
>> ret_from_fork+0x1f/0x40
>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffff810c63f0>] ?
>> kthread_worker_fn+0x170/0x170
>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel: Code: b8 b0 1e 04 00 48
>> 89 e5 74 11 40 80 ff 14 ba d0 78 02 00 b8 60 3d 08 00 0f 45 c2 5d c3
>> 66 0f 1f
>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel: RIP
>> [<ffffffffa00e6cf5>] drm_dp_sink_bpc+0x5/0xb0 [drm_kms_helper]
>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  RSP <ffff880309f23b48>
>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel: CR2: 000000000000011b
>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel: ---[ end trace
>> d3270996301ba013 ]---
>>
>> Possibly MST related.
>>
>> Dave.
>
Mario Kleiner Aug. 7, 2016, 4:10 p.m. UTC | #4
On 08/03/2016 02:03 PM, Mario Kleiner wrote:
> On 08/03/2016 08:09 AM, Daniel Vetter wrote:
>> On Wed, Aug 03, 2016 at 01:07:12PM +1000, Dave Airlie wrote:
>>> On 6 July 2016 at 20:05, Mario Kleiner <mario.kleiner.de@gmail.com>
>>> wrote:
>>>> For DP sinks which don't expose color depth via EDID, use
>>>> the drm_dp_sink_bpc() helper to derive the bpc of the sink.
>>>>
>>>> This should handle DP native sinks with the "Assume 6 bpc if EDID
>>>> doesn't tell us" as mandated by DP spec. It gives more accurate
>>>> values for DP->legacy converters for HDMI, DVI and VGA.
>>>
>>> Haswell says no.
>>
>> Yup indeed, sorry for missing that. Tomeu and Mika Kahola are working on
>> some fancy new dp helper to probe all that, and as part of that suitably
>> fill out connector->display_info, too. That would allow both the
>> inversion, and the dpcd transaction from within atomic_check (which is
>> kinda not that cool either).
>> -Daniel
>>
>
> Ups, sorry. They were only successfully tested with Ironlake and
> Ivybridge, non-MST, all the Intel hw i have here.
>
> Anyway, patches 1+2 and 5 are independent of those and will fix existing
> bugs and regressions in stable kernels. Patch 1 fixes what the commit
> reverted in patch 2 was fixing. Patch 2 fixes the DP->legacy regressions
> which affect my users, patch 5 adds robustness for DVI sinks in general,
> making full use of EDID 1.3 info.
>
> Maybe the logic in patch 3 can be somehow useful for Tomeu and Mika, as
> it was tested with different dp -> xx adapters. Happy to review or test
> once they have stuff ready.
>

So, how to proceed? Will the good ones be merged for 4.8? I could also 
add a NULL-Ptr check to patch 4 and let it fall back to reporting 8 bpc 
in case of dp-mst trouble if that is preferred for the time being?

I'd really like to get at least the regression fixes in before Tomeu or 
Mika, as i assume once their work gets merged, touching the same code in 
intel-kms, it will be impossible to back port my fixes or their work to 
stable kernels.

Thanks,
-mario


> thanks,
> -mario
>
>>>
>>> ug 03 12:58:46 tyrion-bne-redhat-com kernel: fbcon: inteldrmfb (fb0)
>>> is primary device
>>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel: BUG: unable to handle
>>> kernel NULL pointer dereference at 000000000000011b
>>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel: IP: [<ffffffffa00e6cf5>]
>>> drm_dp_sink_bpc+0x5/0xb0 [drm_kms_helper]
>>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel: PGD 0
>>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel: Oops: 0000 [#1] SMP
>>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel: Modules linked in: i915
>>> ccm xt_CHECKSUM ipt_MASQUERADE nf_nat_masquerade_ipv4 tun
>>> ip6t_rpfilter ip6t_
>>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  videobuf2_core
>>> snd_hda_codec videodev mei_me mei snd_hwdep snd_seq snd_hda_core
>>> rtsx_pci media i2c_i
>>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel: CPU: 1 PID: 752 Comm:
>>> kworker/1:3 Not tainted 4.7.0+ #12
>>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel: Hardware name: LENOVO
>>> 20ARS25701/20ARS25701, BIOS GJET72WW (2.22 ) 02/21/2014
>>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel: Workqueue: events_long
>>> drm_dp_mst_link_probe_work [drm_kms_helper]
>>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel: task: ffff880308583a80
>>> task.stack: ffff880309f20000
>>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel: RIP:
>>> 0010:[<ffffffffa00e6cf5>]  [<ffffffffa00e6cf5>]
>>> drm_dp_sink_bpc+0x5/0xb0 [drm_kms_helper]
>>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel: RSP:
>>> 0018:ffff880309f23b48  EFLAGS: 00010202
>>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel: RAX: 000000000000000a
>>> RBX: 0000000000000006 RCX: 0000000000000000
>>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel: RDX: 0000000000000000
>>> RSI: 0000000000000127 RDI: 0000000000000116
>>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel: RBP: ffff880309f23b50
>>> R08: ffff880309734800 R09: 0000000000000024
>>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel: R10: 0000000000000000
>>> R11: 0000000000000000 R12: ffff880309737800
>>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel: R13: ffff88030a334000
>>> R14: ffff880309737000 R15: ffff880309737800
>>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel: FS:
>>> 0000000000000000(0000) GS:ffff88031e240000(0000)
>>> knlGS:0000000000000000
>>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel: CS:  0010 DS: 0000 ES:
>>> 0000 CR0: 0000000080050033
>>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel: CR2: 000000000000011b
>>> CR3: 0000000001c06000 CR4: 00000000001406e0
>>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel: Stack:
>>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  ffffffffa09d4295
>>> ffff880309f23bd8 ffffffffa09a7c1f ffffffff8122544d
>>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  ffff880306660258
>>> ffff880306660000 0000000009737800 ffff88030a331000
>>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  0100880300000024
>>> ffff880309f23bb8 ffffffff00000024 ffff880309737800
>>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel: Call Trace:
>>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffffa09d4295>] ?
>>> intel_dp_sink_bpc+0x25/0x30 [i915]
>>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffffa09a7c1f>]
>>> intel_atomic_check+0xacf/0x1250 [i915]
>>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffff8122544d>] ?
>>> __kmalloc_track_caller+0x12d/0x210
>>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffffa0097ea7>]
>>> drm_atomic_check_only+0x187/0x610 [drm]
>>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffffa0098857>] ?
>>> drm_atomic_add_affected_connectors+0x27/0xf0 [drm]
>>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffffa0098347>]
>>> drm_atomic_commit+0x17/0x60 [drm]
>>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffffa00f4e0c>]
>>> restore_fbdev_mode+0x14c/0x260 [drm_kms_helper]
>>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffffa00f6a23>]
>>> drm_fb_helper_restore_fbdev_mode_unlocked+0x33/0x80 [drm_kms_helper]
>>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffffa00f6a9d>]
>>> drm_fb_helper_set_par+0x2d/0x50 [drm_kms_helper]
>>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffffa00f69b8>]
>>> drm_fb_helper_hotplug_event+0x148/0x180 [drm_kms_helper]
>>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffffa09c238a>]
>>> intel_fbdev_output_poll_changed+0x1a/0x20 [i915]
>>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffffa00e79c7>]
>>> drm_kms_helper_hotplug_event+0x27/0x30 [drm_kms_helper]
>>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffffa09cafa5>]
>>> intel_dp_mst_hotplug+0x15/0x20 [i915]
>>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffffa00ee31a>]
>>> drm_dp_send_link_address+0x19a/0x220 [drm_kms_helper]
>>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffff810df553>] ?
>>> put_prev_entity+0x33/0x410
>>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffff8111280b>] ?
>>> add_timer_on+0xdb/0x1b0
>>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffff8102c766>] ?
>>> __switch_to+0x2b6/0x600
>>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffff810e361e>] ?
>>> pick_next_task_fair+0x10e/0x4d0
>>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffffa00ee44d>]
>>> drm_dp_check_and_send_link_address+0xad/0xc0 [drm_kms_helper]
>>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffffa00ee4b7>]
>>> drm_dp_mst_link_probe_work+0x57/0xb0 [drm_kms_helper]
>>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffff810c086f>]
>>> process_one_work+0x15f/0x410
>>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffff810c0b6e>]
>>> worker_thread+0x4e/0x480
>>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffff810c0b20>] ?
>>> process_one_work+0x410/0x410
>>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffff810c0b20>] ?
>>> process_one_work+0x410/0x410
>>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffff810c64c8>]
>>> kthread+0xd8/0xf0
>>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffff817d527f>]
>>> ret_from_fork+0x1f/0x40
>>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  [<ffffffff810c63f0>] ?
>>> kthread_worker_fn+0x170/0x170
>>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel: Code: b8 b0 1e 04 00 48
>>> 89 e5 74 11 40 80 ff 14 ba d0 78 02 00 b8 60 3d 08 00 0f 45 c2 5d c3
>>> 66 0f 1f
>>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel: RIP
>>> [<ffffffffa00e6cf5>] drm_dp_sink_bpc+0x5/0xb0 [drm_kms_helper]
>>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel:  RSP <ffff880309f23b48>
>>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel: CR2: 000000000000011b
>>> Aug 03 12:58:46 tyrion-bne-redhat-com kernel: ---[ end trace
>>> d3270996301ba013 ]---
>>>
>>> Possibly MST related.
>>>
>>> Dave.
>>
diff mbox

Patch

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index c7854f4..1a5287f 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -12212,11 +12212,27 @@  connected_sink_compute_bpp(struct intel_connector *connector,
 		pipe_config->pipe_bpp = connector->base.display_info.bpc*3;
 	}
 
-	/* Clamp bpp to 8 on screens without EDID 1.4 */
-	if (connector->base.display_info.bpc == 0 && bpp > 24) {
-		DRM_DEBUG_KMS("clamping display bpp (was %d) to default limit of 24\n",
-			      bpp);
-		pipe_config->pipe_bpp = 24;
+	/* Clamp bpp to default limit on screens without EDID 1.4 */
+	if (connector->base.display_info.bpc == 0) {
+		int type = connector->base.connector_type;
+		int clamp_bpp = 24;
+
+		/* On DisplayPort try harder to find sink bpc */
+		if (type == DRM_MODE_CONNECTOR_DisplayPort ||
+		    type == DRM_MODE_CONNECTOR_eDP) {
+			int sink_bpc = intel_dp_sink_bpc(&connector->base);
+
+			if (sink_bpc) {
+				DRM_DEBUG_KMS("DP sink with bpc %d\n", sink_bpc);
+				clamp_bpp = 3 * sink_bpc;
+			}
+		}
+
+		if (bpp > clamp_bpp) {
+			DRM_DEBUG_KMS("clamping display bpp (was %d) to default limit of %d\n",
+				      bpp, clamp_bpp);
+			pipe_config->pipe_bpp = clamp_bpp;
+		}
 	}
 }
 
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index ffa43ec..d8dab0b 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -5689,3 +5689,10 @@  void intel_dp_mst_resume(struct drm_device *dev)
 		}
 	}
 }
+
+/* XXX Only supports up to 1 downstream port atm. */
+int intel_dp_sink_bpc(struct drm_connector *connector)
+{
+	struct intel_dp *intel_dp = intel_attached_dp(connector);
+	return drm_dp_sink_bpc(intel_dp->dpcd, intel_dp->downstream_ports, 0);
+}
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 089a425..e8feac1 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -1335,6 +1335,7 @@  void intel_edp_panel_off(struct intel_dp *intel_dp);
 void intel_dp_add_properties(struct intel_dp *intel_dp, struct drm_connector *connector);
 void intel_dp_mst_suspend(struct drm_device *dev);
 void intel_dp_mst_resume(struct drm_device *dev);
+int intel_dp_sink_bpc(struct drm_connector *connector);
 int intel_dp_max_link_rate(struct intel_dp *intel_dp);
 int intel_dp_rate_select(struct intel_dp *intel_dp, int rate);
 void intel_dp_hot_plug(struct intel_encoder *intel_encoder);