[v10,03/11] drm/sun4i: dsi: Fix video start delay computation
diff mbox series

Message ID 20190520090318.27570-4-jagan@amarulasolutions.com
State New
Headers show
Series
  • drm/sun4i: dsi: Fixes/updates (A33 reworked!)
Related show

Commit Message

Jagan Teki May 20, 2019, 9:03 a.m. UTC
The current code is computing vertical video start delay as

delay = mode->vtotal - (mode->vsync_end - mode->vdisplay) + start;

On which the second parameter

mode->vsync_end - mode->vdisplay = front porch + sync timings

according to "DRM kernel-internal display mode structure" in
include/drm/drm_modes.h

With adding additional sync timings, the desired video start delay
value as 510 for "bananapi,s070wv20-ct16" panel timings which indeed
trigger panel flip_done timed out as:

 WARNING: CPU: 0 PID: 31 at drivers/gpu/drm/drm_atomic_helper.c:1429 drm_atomic_helper_wait_for_vblanks.part.1+0x298/0x2a0
 [CRTC:46:crtc-0] vblank wait timed out
 Modules linked in:
 CPU: 0 PID: 31 Comm: kworker/0:1 Not tainted 5.1.0-next-20190514-00029-g09e5b0ed0a58 #18
 Hardware name: Allwinner sun8i Family
 Workqueue: events deferred_probe_work_func
 [<c010ed54>] (unwind_backtrace) from [<c010b76c>] (show_stack+0x10/0x14)
 [<c010b76c>] (show_stack) from [<c0688c70>] (dump_stack+0x84/0x98)
 [<c0688c70>] (dump_stack) from [<c011d9e4>] (__warn+0xfc/0x114)
 [<c011d9e4>] (__warn) from [<c011da40>] (warn_slowpath_fmt+0x44/0x68)
 [<c011da40>] (warn_slowpath_fmt) from [<c040cd50>] (drm_atomic_helper_wait_for_vblanks.part.1+0x298/0x2a0)
 [<c040cd50>] (drm_atomic_helper_wait_for_vblanks.part.1) from [<c040e694>] (drm_atomic_helper_commit_tail_rpm+0x5c/0x6c)
 [<c040e694>] (drm_atomic_helper_commit_tail_rpm) from [<c040e4dc>] (commit_tail+0x40/0x6c)
 [<c040e4dc>] (commit_tail) from [<c040e5cc>] (drm_atomic_helper_commit+0xbc/0x128)
 [<c040e5cc>] (drm_atomic_helper_commit) from [<c0411b64>] (restore_fbdev_mode_atomic+0x1cc/0x1dc)
 [<c0411b64>] (restore_fbdev_mode_atomic) from [<c04156f8>] (drm_fb_helper_restore_fbdev_mode_unlocked+0x54/0xa0)
 [<c04156f8>] (drm_fb_helper_restore_fbdev_mode_unlocked) from [<c0415774>] (drm_fb_helper_set_par+0x30/0x54)
 [<c0415774>] (drm_fb_helper_set_par) from [<c03ad450>] (fbcon_init+0x560/0x5ac)
 [<c03ad450>] (fbcon_init) from [<c03eb8a0>] (visual_init+0xbc/0x104)
 [<c03eb8a0>] (visual_init) from [<c03ed1b8>] (do_bind_con_driver+0x1b0/0x390)
 [<c03ed1b8>] (do_bind_con_driver) from [<c03ed780>] (do_take_over_console+0x13c/0x1c4)
 [<c03ed780>] (do_take_over_console) from [<c03ad800>] (do_fbcon_takeover+0x74/0xcc)
 [<c03ad800>] (do_fbcon_takeover) from [<c013c9c8>] (notifier_call_chain+0x44/0x84)
 [<c013c9c8>] (notifier_call_chain) from [<c013cd20>] (__blocking_notifier_call_chain+0x48/0x60)
 [<c013cd20>] (__blocking_notifier_call_chain) from [<c013cd50>] (blocking_notifier_call_chain+0x18/0x20)
 [<c013cd50>] (blocking_notifier_call_chain) from [<c03a6e44>] (register_framebuffer+0x1e0/0x2f8)
 [<c03a6e44>] (register_framebuffer) from [<c04153c0>] (__drm_fb_helper_initial_config_and_unlock+0x2fc/0x50c)
 [<c04153c0>] (__drm_fb_helper_initial_config_and_unlock) from [<c04158c8>] (drm_fbdev_client_hotplug+0xe8/0x1b8)
 [<c04158c8>] (drm_fbdev_client_hotplug) from [<c0415a20>] (drm_fbdev_generic_setup+0x88/0x118)
 [<c0415a20>] (drm_fbdev_generic_setup) from [<c043f060>] (sun4i_drv_bind+0x128/0x160)
 [<c043f060>] (sun4i_drv_bind) from [<c044b598>] (try_to_bring_up_master+0x164/0x1a0)
 [<c044b598>] (try_to_bring_up_master) from [<c044b668>] (__component_add+0x94/0x140)
 [<c044b668>] (__component_add) from [<c0445e1c>] (sun6i_dsi_probe+0x144/0x234)
 [<c0445e1c>] (sun6i_dsi_probe) from [<c0452ef4>] (platform_drv_probe+0x48/0x9c)
 [<c0452ef4>] (platform_drv_probe) from [<c04512cc>] (really_probe+0x1dc/0x2c8)
 [<c04512cc>] (really_probe) from [<c0451518>] (driver_probe_device+0x60/0x160)
 [<c0451518>] (driver_probe_device) from [<c044f7a4>] (bus_for_each_drv+0x74/0xb8)
 [<c044f7a4>] (bus_for_each_drv) from [<c045107c>] (__device_attach+0xd0/0x13c)
 [<c045107c>] (__device_attach) from [<c0450474>] (bus_probe_device+0x84/0x8c)
 [<c0450474>] (bus_probe_device) from [<c0450900>] (deferred_probe_work_func+0x64/0x90)
 [<c0450900>] (deferred_probe_work_func) from [<c0135970>] (process_one_work+0x204/0x420)
 [<c0135970>] (process_one_work) from [<c013690c>] (worker_thread+0x274/0x5a0)
 [<c013690c>] (worker_thread) from [<c013b3d8>] (kthread+0x11c/0x14c)
 [<c013b3d8>] (kthread) from [<c01010e8>] (ret_from_fork+0x14/0x2c)
 Exception stack(0xde539fb0 to 0xde539ff8)
 9fa0:                                     00000000 00000000 00000000 00000000
 9fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
 9fe0: 00000000 00000000 00000000 00000000 00000013 00000000
 ---[ end trace 495200a78b24980e ]---
 random: fast init done
 [drm:drm_atomic_helper_wait_for_dependencies] *ERROR* [CRTC:46:crtc-0] flip_done timed out
 [drm:drm_atomic_helper_wait_for_dependencies] *ERROR* [CONNECTOR:48:DSI-1] flip_done timed out
 [drm:drm_atomic_helper_wait_for_dependencies] *ERROR* [PLANE:30:plane-0] flip_done timed out

But the expected video start delay value is 513 which states that
the second parameter on the computation is "front porch" value
(no sync timings included).

This is clearly confirmed from the legacy [1] and new [2] bsp codes
that the second parameter on the video start delay is "front porch"

Here is the detailed evidence for calculating front porch as per
bsp code.

vfp = panel->lcd_vt - panel->lcd_y - panel->lcd_vbp
=> (panel->lcd_vt) - panel->lcd_y - panel->lcd_vbp
=> (tt->ver_front_porch + lcdp->panel_info.lcd_vbp
    + lcdp->panel_info.lcd_y) -  panel->lcd_y - panel->lcd_vbp
=> tt->ver_front_porch

Which is mode->vsync_start - mode->vdisplay according to
"DRM kernel-internal display mode structure" in include/drm/drm_modes.h

This patch fix this by updating the video start delay to use
front porch value.

[2] https://github.com/BPI-SINOVOIP/BPI-M2M-bsp/blob/master/linux-sunxi/drivers/video/sunxi/disp/de/disp_lcd.c#L2051
[1] https://github.com/BPI-SINOVOIP/BPI-M2M-bsp/blob/master/linux-sunxi/drivers/video/sunxi/disp/de/lowlevel_sun8iw5/de_dsi.c#L803

Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
---
 drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Maxime Ripard May 23, 2019, 8:38 p.m. UTC | #1
On Mon, May 20, 2019 at 02:33:10PM +0530, Jagan Teki wrote:
> The current code is computing vertical video start delay as
>
> delay = mode->vtotal - (mode->vsync_end - mode->vdisplay) + start;
>
> On which the second parameter
>
> mode->vsync_end - mode->vdisplay = front porch + sync timings
>
> according to "DRM kernel-internal display mode structure" in
> include/drm/drm_modes.h
>
> With adding additional sync timings, the desired video start delay
> value as 510 for "bananapi,s070wv20-ct16" panel timings which indeed
> trigger panel flip_done timed out as:
>
>  WARNING: CPU: 0 PID: 31 at drivers/gpu/drm/drm_atomic_helper.c:1429 drm_atomic_helper_wait_for_vblanks.part.1+0x298/0x2a0
>  [CRTC:46:crtc-0] vblank wait timed out
>  Modules linked in:
>  CPU: 0 PID: 31 Comm: kworker/0:1 Not tainted 5.1.0-next-20190514-00029-g09e5b0ed0a58 #18
>  Hardware name: Allwinner sun8i Family
>  Workqueue: events deferred_probe_work_func
>  [<c010ed54>] (unwind_backtrace) from [<c010b76c>] (show_stack+0x10/0x14)
>  [<c010b76c>] (show_stack) from [<c0688c70>] (dump_stack+0x84/0x98)
>  [<c0688c70>] (dump_stack) from [<c011d9e4>] (__warn+0xfc/0x114)
>  [<c011d9e4>] (__warn) from [<c011da40>] (warn_slowpath_fmt+0x44/0x68)
>  [<c011da40>] (warn_slowpath_fmt) from [<c040cd50>] (drm_atomic_helper_wait_for_vblanks.part.1+0x298/0x2a0)
>  [<c040cd50>] (drm_atomic_helper_wait_for_vblanks.part.1) from [<c040e694>] (drm_atomic_helper_commit_tail_rpm+0x5c/0x6c)
>  [<c040e694>] (drm_atomic_helper_commit_tail_rpm) from [<c040e4dc>] (commit_tail+0x40/0x6c)
>  [<c040e4dc>] (commit_tail) from [<c040e5cc>] (drm_atomic_helper_commit+0xbc/0x128)
>  [<c040e5cc>] (drm_atomic_helper_commit) from [<c0411b64>] (restore_fbdev_mode_atomic+0x1cc/0x1dc)
>  [<c0411b64>] (restore_fbdev_mode_atomic) from [<c04156f8>] (drm_fb_helper_restore_fbdev_mode_unlocked+0x54/0xa0)
>  [<c04156f8>] (drm_fb_helper_restore_fbdev_mode_unlocked) from [<c0415774>] (drm_fb_helper_set_par+0x30/0x54)
>  [<c0415774>] (drm_fb_helper_set_par) from [<c03ad450>] (fbcon_init+0x560/0x5ac)
>  [<c03ad450>] (fbcon_init) from [<c03eb8a0>] (visual_init+0xbc/0x104)
>  [<c03eb8a0>] (visual_init) from [<c03ed1b8>] (do_bind_con_driver+0x1b0/0x390)
>  [<c03ed1b8>] (do_bind_con_driver) from [<c03ed780>] (do_take_over_console+0x13c/0x1c4)
>  [<c03ed780>] (do_take_over_console) from [<c03ad800>] (do_fbcon_takeover+0x74/0xcc)
>  [<c03ad800>] (do_fbcon_takeover) from [<c013c9c8>] (notifier_call_chain+0x44/0x84)
>  [<c013c9c8>] (notifier_call_chain) from [<c013cd20>] (__blocking_notifier_call_chain+0x48/0x60)
>  [<c013cd20>] (__blocking_notifier_call_chain) from [<c013cd50>] (blocking_notifier_call_chain+0x18/0x20)
>  [<c013cd50>] (blocking_notifier_call_chain) from [<c03a6e44>] (register_framebuffer+0x1e0/0x2f8)
>  [<c03a6e44>] (register_framebuffer) from [<c04153c0>] (__drm_fb_helper_initial_config_and_unlock+0x2fc/0x50c)
>  [<c04153c0>] (__drm_fb_helper_initial_config_and_unlock) from [<c04158c8>] (drm_fbdev_client_hotplug+0xe8/0x1b8)
>  [<c04158c8>] (drm_fbdev_client_hotplug) from [<c0415a20>] (drm_fbdev_generic_setup+0x88/0x118)
>  [<c0415a20>] (drm_fbdev_generic_setup) from [<c043f060>] (sun4i_drv_bind+0x128/0x160)
>  [<c043f060>] (sun4i_drv_bind) from [<c044b598>] (try_to_bring_up_master+0x164/0x1a0)
>  [<c044b598>] (try_to_bring_up_master) from [<c044b668>] (__component_add+0x94/0x140)
>  [<c044b668>] (__component_add) from [<c0445e1c>] (sun6i_dsi_probe+0x144/0x234)
>  [<c0445e1c>] (sun6i_dsi_probe) from [<c0452ef4>] (platform_drv_probe+0x48/0x9c)
>  [<c0452ef4>] (platform_drv_probe) from [<c04512cc>] (really_probe+0x1dc/0x2c8)
>  [<c04512cc>] (really_probe) from [<c0451518>] (driver_probe_device+0x60/0x160)
>  [<c0451518>] (driver_probe_device) from [<c044f7a4>] (bus_for_each_drv+0x74/0xb8)
>  [<c044f7a4>] (bus_for_each_drv) from [<c045107c>] (__device_attach+0xd0/0x13c)
>  [<c045107c>] (__device_attach) from [<c0450474>] (bus_probe_device+0x84/0x8c)
>  [<c0450474>] (bus_probe_device) from [<c0450900>] (deferred_probe_work_func+0x64/0x90)
>  [<c0450900>] (deferred_probe_work_func) from [<c0135970>] (process_one_work+0x204/0x420)
>  [<c0135970>] (process_one_work) from [<c013690c>] (worker_thread+0x274/0x5a0)
>  [<c013690c>] (worker_thread) from [<c013b3d8>] (kthread+0x11c/0x14c)
>  [<c013b3d8>] (kthread) from [<c01010e8>] (ret_from_fork+0x14/0x2c)
>  Exception stack(0xde539fb0 to 0xde539ff8)
>  9fa0:                                     00000000 00000000 00000000 00000000
>  9fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
>  9fe0: 00000000 00000000 00000000 00000000 00000013 00000000
>  ---[ end trace 495200a78b24980e ]---
>  random: fast init done
>  [drm:drm_atomic_helper_wait_for_dependencies] *ERROR* [CRTC:46:crtc-0] flip_done timed out
>  [drm:drm_atomic_helper_wait_for_dependencies] *ERROR* [CONNECTOR:48:DSI-1] flip_done timed out
>  [drm:drm_atomic_helper_wait_for_dependencies] *ERROR* [PLANE:30:plane-0] flip_done timed out
>
> But the expected video start delay value is 513 which states that
> the second parameter on the computation is "front porch" value
> (no sync timings included).
>
> This is clearly confirmed from the legacy [1] and new [2] bsp codes
> that the second parameter on the video start delay is "front porch"
>
> Here is the detailed evidence for calculating front porch as per
> bsp code.
>
> vfp = panel->lcd_vt - panel->lcd_y - panel->lcd_vbp
> => (panel->lcd_vt) - panel->lcd_y - panel->lcd_vbp
> => (tt->ver_front_porch + lcdp->panel_info.lcd_vbp
>     + lcdp->panel_info.lcd_y) -  panel->lcd_y - panel->lcd_vbp
> => tt->ver_front_porch

The comment on patch 1 still applies on this patch

Maxime

--
Maxime Ripard, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com
Jagan Teki May 24, 2019, 10:26 a.m. UTC | #2
On Fri, May 24, 2019 at 2:18 AM Maxime Ripard <maxime.ripard@bootlin.com> wrote:
>
> On Mon, May 20, 2019 at 02:33:10PM +0530, Jagan Teki wrote:
> > The current code is computing vertical video start delay as
> >
> > delay = mode->vtotal - (mode->vsync_end - mode->vdisplay) + start;
> >
> > On which the second parameter
> >
> > mode->vsync_end - mode->vdisplay = front porch + sync timings
> >
> > according to "DRM kernel-internal display mode structure" in
> > include/drm/drm_modes.h
> >
> > With adding additional sync timings, the desired video start delay
> > value as 510 for "bananapi,s070wv20-ct16" panel timings which indeed
> > trigger panel flip_done timed out as:
> >
> >  WARNING: CPU: 0 PID: 31 at drivers/gpu/drm/drm_atomic_helper.c:1429 drm_atomic_helper_wait_for_vblanks.part.1+0x298/0x2a0
> >  [CRTC:46:crtc-0] vblank wait timed out
> >  Modules linked in:
> >  CPU: 0 PID: 31 Comm: kworker/0:1 Not tainted 5.1.0-next-20190514-00029-g09e5b0ed0a58 #18
> >  Hardware name: Allwinner sun8i Family
> >  Workqueue: events deferred_probe_work_func
> >  [<c010ed54>] (unwind_backtrace) from [<c010b76c>] (show_stack+0x10/0x14)
> >  [<c010b76c>] (show_stack) from [<c0688c70>] (dump_stack+0x84/0x98)
> >  [<c0688c70>] (dump_stack) from [<c011d9e4>] (__warn+0xfc/0x114)
> >  [<c011d9e4>] (__warn) from [<c011da40>] (warn_slowpath_fmt+0x44/0x68)
> >  [<c011da40>] (warn_slowpath_fmt) from [<c040cd50>] (drm_atomic_helper_wait_for_vblanks.part.1+0x298/0x2a0)
> >  [<c040cd50>] (drm_atomic_helper_wait_for_vblanks.part.1) from [<c040e694>] (drm_atomic_helper_commit_tail_rpm+0x5c/0x6c)
> >  [<c040e694>] (drm_atomic_helper_commit_tail_rpm) from [<c040e4dc>] (commit_tail+0x40/0x6c)
> >  [<c040e4dc>] (commit_tail) from [<c040e5cc>] (drm_atomic_helper_commit+0xbc/0x128)
> >  [<c040e5cc>] (drm_atomic_helper_commit) from [<c0411b64>] (restore_fbdev_mode_atomic+0x1cc/0x1dc)
> >  [<c0411b64>] (restore_fbdev_mode_atomic) from [<c04156f8>] (drm_fb_helper_restore_fbdev_mode_unlocked+0x54/0xa0)
> >  [<c04156f8>] (drm_fb_helper_restore_fbdev_mode_unlocked) from [<c0415774>] (drm_fb_helper_set_par+0x30/0x54)
> >  [<c0415774>] (drm_fb_helper_set_par) from [<c03ad450>] (fbcon_init+0x560/0x5ac)
> >  [<c03ad450>] (fbcon_init) from [<c03eb8a0>] (visual_init+0xbc/0x104)
> >  [<c03eb8a0>] (visual_init) from [<c03ed1b8>] (do_bind_con_driver+0x1b0/0x390)
> >  [<c03ed1b8>] (do_bind_con_driver) from [<c03ed780>] (do_take_over_console+0x13c/0x1c4)
> >  [<c03ed780>] (do_take_over_console) from [<c03ad800>] (do_fbcon_takeover+0x74/0xcc)
> >  [<c03ad800>] (do_fbcon_takeover) from [<c013c9c8>] (notifier_call_chain+0x44/0x84)
> >  [<c013c9c8>] (notifier_call_chain) from [<c013cd20>] (__blocking_notifier_call_chain+0x48/0x60)
> >  [<c013cd20>] (__blocking_notifier_call_chain) from [<c013cd50>] (blocking_notifier_call_chain+0x18/0x20)
> >  [<c013cd50>] (blocking_notifier_call_chain) from [<c03a6e44>] (register_framebuffer+0x1e0/0x2f8)
> >  [<c03a6e44>] (register_framebuffer) from [<c04153c0>] (__drm_fb_helper_initial_config_and_unlock+0x2fc/0x50c)
> >  [<c04153c0>] (__drm_fb_helper_initial_config_and_unlock) from [<c04158c8>] (drm_fbdev_client_hotplug+0xe8/0x1b8)
> >  [<c04158c8>] (drm_fbdev_client_hotplug) from [<c0415a20>] (drm_fbdev_generic_setup+0x88/0x118)
> >  [<c0415a20>] (drm_fbdev_generic_setup) from [<c043f060>] (sun4i_drv_bind+0x128/0x160)
> >  [<c043f060>] (sun4i_drv_bind) from [<c044b598>] (try_to_bring_up_master+0x164/0x1a0)
> >  [<c044b598>] (try_to_bring_up_master) from [<c044b668>] (__component_add+0x94/0x140)
> >  [<c044b668>] (__component_add) from [<c0445e1c>] (sun6i_dsi_probe+0x144/0x234)
> >  [<c0445e1c>] (sun6i_dsi_probe) from [<c0452ef4>] (platform_drv_probe+0x48/0x9c)
> >  [<c0452ef4>] (platform_drv_probe) from [<c04512cc>] (really_probe+0x1dc/0x2c8)
> >  [<c04512cc>] (really_probe) from [<c0451518>] (driver_probe_device+0x60/0x160)
> >  [<c0451518>] (driver_probe_device) from [<c044f7a4>] (bus_for_each_drv+0x74/0xb8)
> >  [<c044f7a4>] (bus_for_each_drv) from [<c045107c>] (__device_attach+0xd0/0x13c)
> >  [<c045107c>] (__device_attach) from [<c0450474>] (bus_probe_device+0x84/0x8c)
> >  [<c0450474>] (bus_probe_device) from [<c0450900>] (deferred_probe_work_func+0x64/0x90)
> >  [<c0450900>] (deferred_probe_work_func) from [<c0135970>] (process_one_work+0x204/0x420)
> >  [<c0135970>] (process_one_work) from [<c013690c>] (worker_thread+0x274/0x5a0)
> >  [<c013690c>] (worker_thread) from [<c013b3d8>] (kthread+0x11c/0x14c)
> >  [<c013b3d8>] (kthread) from [<c01010e8>] (ret_from_fork+0x14/0x2c)
> >  Exception stack(0xde539fb0 to 0xde539ff8)
> >  9fa0:                                     00000000 00000000 00000000 00000000
> >  9fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
> >  9fe0: 00000000 00000000 00000000 00000000 00000013 00000000
> >  ---[ end trace 495200a78b24980e ]---
> >  random: fast init done
> >  [drm:drm_atomic_helper_wait_for_dependencies] *ERROR* [CRTC:46:crtc-0] flip_done timed out
> >  [drm:drm_atomic_helper_wait_for_dependencies] *ERROR* [CONNECTOR:48:DSI-1] flip_done timed out
> >  [drm:drm_atomic_helper_wait_for_dependencies] *ERROR* [PLANE:30:plane-0] flip_done timed out
> >
> > But the expected video start delay value is 513 which states that
> > the second parameter on the computation is "front porch" value
> > (no sync timings included).
> >
> > This is clearly confirmed from the legacy [1] and new [2] bsp codes
> > that the second parameter on the video start delay is "front porch"
> >
> > Here is the detailed evidence for calculating front porch as per
> > bsp code.
> >
> > vfp = panel->lcd_vt - panel->lcd_y - panel->lcd_vbp
> > => (panel->lcd_vt) - panel->lcd_y - panel->lcd_vbp
> > => (tt->ver_front_porch + lcdp->panel_info.lcd_vbp
> >     + lcdp->panel_info.lcd_y) -  panel->lcd_y - panel->lcd_vbp
> > => tt->ver_front_porch
>
> The comment on patch 1 still applies on this patch

Thanks, I have responded on that. Same applies here.
Chen-Yu Tsai June 21, 2019, 8:35 a.m. UTC | #3
On Fri, May 24, 2019 at 6:27 PM Jagan Teki <jagan@amarulasolutions.com> wrote:
>
> On Fri, May 24, 2019 at 2:18 AM Maxime Ripard <maxime.ripard@bootlin.com> wrote:
> >
> > On Mon, May 20, 2019 at 02:33:10PM +0530, Jagan Teki wrote:
> > > The current code is computing vertical video start delay as
> > >
> > > delay = mode->vtotal - (mode->vsync_end - mode->vdisplay) + start;
> > >
> > > On which the second parameter
> > >
> > > mode->vsync_end - mode->vdisplay = front porch + sync timings
> > >
> > > according to "DRM kernel-internal display mode structure" in
> > > include/drm/drm_modes.h
> > >
> > > With adding additional sync timings, the desired video start delay
> > > value as 510 for "bananapi,s070wv20-ct16" panel timings which indeed
> > > trigger panel flip_done timed out as:
> > >
> > >  WARNING: CPU: 0 PID: 31 at drivers/gpu/drm/drm_atomic_helper.c:1429 drm_atomic_helper_wait_for_vblanks.part.1+0x298/0x2a0
> > >  [CRTC:46:crtc-0] vblank wait timed out
> > >  Modules linked in:
> > >  CPU: 0 PID: 31 Comm: kworker/0:1 Not tainted 5.1.0-next-20190514-00029-g09e5b0ed0a58 #18
> > >  Hardware name: Allwinner sun8i Family
> > >  Workqueue: events deferred_probe_work_func
> > >  [<c010ed54>] (unwind_backtrace) from [<c010b76c>] (show_stack+0x10/0x14)
> > >  [<c010b76c>] (show_stack) from [<c0688c70>] (dump_stack+0x84/0x98)
> > >  [<c0688c70>] (dump_stack) from [<c011d9e4>] (__warn+0xfc/0x114)
> > >  [<c011d9e4>] (__warn) from [<c011da40>] (warn_slowpath_fmt+0x44/0x68)
> > >  [<c011da40>] (warn_slowpath_fmt) from [<c040cd50>] (drm_atomic_helper_wait_for_vblanks.part.1+0x298/0x2a0)
> > >  [<c040cd50>] (drm_atomic_helper_wait_for_vblanks.part.1) from [<c040e694>] (drm_atomic_helper_commit_tail_rpm+0x5c/0x6c)
> > >  [<c040e694>] (drm_atomic_helper_commit_tail_rpm) from [<c040e4dc>] (commit_tail+0x40/0x6c)
> > >  [<c040e4dc>] (commit_tail) from [<c040e5cc>] (drm_atomic_helper_commit+0xbc/0x128)
> > >  [<c040e5cc>] (drm_atomic_helper_commit) from [<c0411b64>] (restore_fbdev_mode_atomic+0x1cc/0x1dc)
> > >  [<c0411b64>] (restore_fbdev_mode_atomic) from [<c04156f8>] (drm_fb_helper_restore_fbdev_mode_unlocked+0x54/0xa0)
> > >  [<c04156f8>] (drm_fb_helper_restore_fbdev_mode_unlocked) from [<c0415774>] (drm_fb_helper_set_par+0x30/0x54)
> > >  [<c0415774>] (drm_fb_helper_set_par) from [<c03ad450>] (fbcon_init+0x560/0x5ac)
> > >  [<c03ad450>] (fbcon_init) from [<c03eb8a0>] (visual_init+0xbc/0x104)
> > >  [<c03eb8a0>] (visual_init) from [<c03ed1b8>] (do_bind_con_driver+0x1b0/0x390)
> > >  [<c03ed1b8>] (do_bind_con_driver) from [<c03ed780>] (do_take_over_console+0x13c/0x1c4)
> > >  [<c03ed780>] (do_take_over_console) from [<c03ad800>] (do_fbcon_takeover+0x74/0xcc)
> > >  [<c03ad800>] (do_fbcon_takeover) from [<c013c9c8>] (notifier_call_chain+0x44/0x84)
> > >  [<c013c9c8>] (notifier_call_chain) from [<c013cd20>] (__blocking_notifier_call_chain+0x48/0x60)
> > >  [<c013cd20>] (__blocking_notifier_call_chain) from [<c013cd50>] (blocking_notifier_call_chain+0x18/0x20)
> > >  [<c013cd50>] (blocking_notifier_call_chain) from [<c03a6e44>] (register_framebuffer+0x1e0/0x2f8)
> > >  [<c03a6e44>] (register_framebuffer) from [<c04153c0>] (__drm_fb_helper_initial_config_and_unlock+0x2fc/0x50c)
> > >  [<c04153c0>] (__drm_fb_helper_initial_config_and_unlock) from [<c04158c8>] (drm_fbdev_client_hotplug+0xe8/0x1b8)
> > >  [<c04158c8>] (drm_fbdev_client_hotplug) from [<c0415a20>] (drm_fbdev_generic_setup+0x88/0x118)
> > >  [<c0415a20>] (drm_fbdev_generic_setup) from [<c043f060>] (sun4i_drv_bind+0x128/0x160)
> > >  [<c043f060>] (sun4i_drv_bind) from [<c044b598>] (try_to_bring_up_master+0x164/0x1a0)
> > >  [<c044b598>] (try_to_bring_up_master) from [<c044b668>] (__component_add+0x94/0x140)
> > >  [<c044b668>] (__component_add) from [<c0445e1c>] (sun6i_dsi_probe+0x144/0x234)
> > >  [<c0445e1c>] (sun6i_dsi_probe) from [<c0452ef4>] (platform_drv_probe+0x48/0x9c)
> > >  [<c0452ef4>] (platform_drv_probe) from [<c04512cc>] (really_probe+0x1dc/0x2c8)
> > >  [<c04512cc>] (really_probe) from [<c0451518>] (driver_probe_device+0x60/0x160)
> > >  [<c0451518>] (driver_probe_device) from [<c044f7a4>] (bus_for_each_drv+0x74/0xb8)
> > >  [<c044f7a4>] (bus_for_each_drv) from [<c045107c>] (__device_attach+0xd0/0x13c)
> > >  [<c045107c>] (__device_attach) from [<c0450474>] (bus_probe_device+0x84/0x8c)
> > >  [<c0450474>] (bus_probe_device) from [<c0450900>] (deferred_probe_work_func+0x64/0x90)
> > >  [<c0450900>] (deferred_probe_work_func) from [<c0135970>] (process_one_work+0x204/0x420)
> > >  [<c0135970>] (process_one_work) from [<c013690c>] (worker_thread+0x274/0x5a0)
> > >  [<c013690c>] (worker_thread) from [<c013b3d8>] (kthread+0x11c/0x14c)
> > >  [<c013b3d8>] (kthread) from [<c01010e8>] (ret_from_fork+0x14/0x2c)
> > >  Exception stack(0xde539fb0 to 0xde539ff8)
> > >  9fa0:                                     00000000 00000000 00000000 00000000
> > >  9fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
> > >  9fe0: 00000000 00000000 00000000 00000000 00000013 00000000
> > >  ---[ end trace 495200a78b24980e ]---
> > >  random: fast init done
> > >  [drm:drm_atomic_helper_wait_for_dependencies] *ERROR* [CRTC:46:crtc-0] flip_done timed out
> > >  [drm:drm_atomic_helper_wait_for_dependencies] *ERROR* [CONNECTOR:48:DSI-1] flip_done timed out
> > >  [drm:drm_atomic_helper_wait_for_dependencies] *ERROR* [PLANE:30:plane-0] flip_done timed out
> > >
> > > But the expected video start delay value is 513 which states that
> > > the second parameter on the computation is "front porch" value
> > > (no sync timings included).
> > >
> > > This is clearly confirmed from the legacy [1] and new [2] bsp codes
> > > that the second parameter on the video start delay is "front porch"
> > >
> > > Here is the detailed evidence for calculating front porch as per
> > > bsp code.
> > >
> > > vfp = panel->lcd_vt - panel->lcd_y - panel->lcd_vbp
> > > => (panel->lcd_vt) - panel->lcd_y - panel->lcd_vbp
> > > => (tt->ver_front_porch + lcdp->panel_info.lcd_vbp
> > >     + lcdp->panel_info.lcd_y) -  panel->lcd_y - panel->lcd_vbp
> > > => tt->ver_front_porch
> >
> > The comment on patch 1 still applies on this patch
>
> Thanks, I have responded on that. Same applies here.

So this patch fixes the misinterpretation of Allwinner's back porch value,
much like patch 1, but this one is for the vertical back porch. So I think
you should follow the same advice I gave you for patch 1.

ChenYu
Jagan Teki June 24, 2019, 8:52 a.m. UTC | #4
On Fri, Jun 21, 2019 at 2:05 PM Chen-Yu Tsai <wens@csie.org> wrote:
>
> On Fri, May 24, 2019 at 6:27 PM Jagan Teki <jagan@amarulasolutions.com> wrote:
> >
> > On Fri, May 24, 2019 at 2:18 AM Maxime Ripard <maxime.ripard@bootlin.com> wrote:
> > >
> > > On Mon, May 20, 2019 at 02:33:10PM +0530, Jagan Teki wrote:
> > > > The current code is computing vertical video start delay as
> > > >
> > > > delay = mode->vtotal - (mode->vsync_end - mode->vdisplay) + start;
> > > >
> > > > On which the second parameter
> > > >
> > > > mode->vsync_end - mode->vdisplay = front porch + sync timings
> > > >
> > > > according to "DRM kernel-internal display mode structure" in
> > > > include/drm/drm_modes.h
> > > >
> > > > With adding additional sync timings, the desired video start delay
> > > > value as 510 for "bananapi,s070wv20-ct16" panel timings which indeed
> > > > trigger panel flip_done timed out as:
> > > >
> > > >  WARNING: CPU: 0 PID: 31 at drivers/gpu/drm/drm_atomic_helper.c:1429 drm_atomic_helper_wait_for_vblanks.part.1+0x298/0x2a0
> > > >  [CRTC:46:crtc-0] vblank wait timed out
> > > >  Modules linked in:
> > > >  CPU: 0 PID: 31 Comm: kworker/0:1 Not tainted 5.1.0-next-20190514-00029-g09e5b0ed0a58 #18
> > > >  Hardware name: Allwinner sun8i Family
> > > >  Workqueue: events deferred_probe_work_func
> > > >  [<c010ed54>] (unwind_backtrace) from [<c010b76c>] (show_stack+0x10/0x14)
> > > >  [<c010b76c>] (show_stack) from [<c0688c70>] (dump_stack+0x84/0x98)
> > > >  [<c0688c70>] (dump_stack) from [<c011d9e4>] (__warn+0xfc/0x114)
> > > >  [<c011d9e4>] (__warn) from [<c011da40>] (warn_slowpath_fmt+0x44/0x68)
> > > >  [<c011da40>] (warn_slowpath_fmt) from [<c040cd50>] (drm_atomic_helper_wait_for_vblanks.part.1+0x298/0x2a0)
> > > >  [<c040cd50>] (drm_atomic_helper_wait_for_vblanks.part.1) from [<c040e694>] (drm_atomic_helper_commit_tail_rpm+0x5c/0x6c)
> > > >  [<c040e694>] (drm_atomic_helper_commit_tail_rpm) from [<c040e4dc>] (commit_tail+0x40/0x6c)
> > > >  [<c040e4dc>] (commit_tail) from [<c040e5cc>] (drm_atomic_helper_commit+0xbc/0x128)
> > > >  [<c040e5cc>] (drm_atomic_helper_commit) from [<c0411b64>] (restore_fbdev_mode_atomic+0x1cc/0x1dc)
> > > >  [<c0411b64>] (restore_fbdev_mode_atomic) from [<c04156f8>] (drm_fb_helper_restore_fbdev_mode_unlocked+0x54/0xa0)
> > > >  [<c04156f8>] (drm_fb_helper_restore_fbdev_mode_unlocked) from [<c0415774>] (drm_fb_helper_set_par+0x30/0x54)
> > > >  [<c0415774>] (drm_fb_helper_set_par) from [<c03ad450>] (fbcon_init+0x560/0x5ac)
> > > >  [<c03ad450>] (fbcon_init) from [<c03eb8a0>] (visual_init+0xbc/0x104)
> > > >  [<c03eb8a0>] (visual_init) from [<c03ed1b8>] (do_bind_con_driver+0x1b0/0x390)
> > > >  [<c03ed1b8>] (do_bind_con_driver) from [<c03ed780>] (do_take_over_console+0x13c/0x1c4)
> > > >  [<c03ed780>] (do_take_over_console) from [<c03ad800>] (do_fbcon_takeover+0x74/0xcc)
> > > >  [<c03ad800>] (do_fbcon_takeover) from [<c013c9c8>] (notifier_call_chain+0x44/0x84)
> > > >  [<c013c9c8>] (notifier_call_chain) from [<c013cd20>] (__blocking_notifier_call_chain+0x48/0x60)
> > > >  [<c013cd20>] (__blocking_notifier_call_chain) from [<c013cd50>] (blocking_notifier_call_chain+0x18/0x20)
> > > >  [<c013cd50>] (blocking_notifier_call_chain) from [<c03a6e44>] (register_framebuffer+0x1e0/0x2f8)
> > > >  [<c03a6e44>] (register_framebuffer) from [<c04153c0>] (__drm_fb_helper_initial_config_and_unlock+0x2fc/0x50c)
> > > >  [<c04153c0>] (__drm_fb_helper_initial_config_and_unlock) from [<c04158c8>] (drm_fbdev_client_hotplug+0xe8/0x1b8)
> > > >  [<c04158c8>] (drm_fbdev_client_hotplug) from [<c0415a20>] (drm_fbdev_generic_setup+0x88/0x118)
> > > >  [<c0415a20>] (drm_fbdev_generic_setup) from [<c043f060>] (sun4i_drv_bind+0x128/0x160)
> > > >  [<c043f060>] (sun4i_drv_bind) from [<c044b598>] (try_to_bring_up_master+0x164/0x1a0)
> > > >  [<c044b598>] (try_to_bring_up_master) from [<c044b668>] (__component_add+0x94/0x140)
> > > >  [<c044b668>] (__component_add) from [<c0445e1c>] (sun6i_dsi_probe+0x144/0x234)
> > > >  [<c0445e1c>] (sun6i_dsi_probe) from [<c0452ef4>] (platform_drv_probe+0x48/0x9c)
> > > >  [<c0452ef4>] (platform_drv_probe) from [<c04512cc>] (really_probe+0x1dc/0x2c8)
> > > >  [<c04512cc>] (really_probe) from [<c0451518>] (driver_probe_device+0x60/0x160)
> > > >  [<c0451518>] (driver_probe_device) from [<c044f7a4>] (bus_for_each_drv+0x74/0xb8)
> > > >  [<c044f7a4>] (bus_for_each_drv) from [<c045107c>] (__device_attach+0xd0/0x13c)
> > > >  [<c045107c>] (__device_attach) from [<c0450474>] (bus_probe_device+0x84/0x8c)
> > > >  [<c0450474>] (bus_probe_device) from [<c0450900>] (deferred_probe_work_func+0x64/0x90)
> > > >  [<c0450900>] (deferred_probe_work_func) from [<c0135970>] (process_one_work+0x204/0x420)
> > > >  [<c0135970>] (process_one_work) from [<c013690c>] (worker_thread+0x274/0x5a0)
> > > >  [<c013690c>] (worker_thread) from [<c013b3d8>] (kthread+0x11c/0x14c)
> > > >  [<c013b3d8>] (kthread) from [<c01010e8>] (ret_from_fork+0x14/0x2c)
> > > >  Exception stack(0xde539fb0 to 0xde539ff8)
> > > >  9fa0:                                     00000000 00000000 00000000 00000000
> > > >  9fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
> > > >  9fe0: 00000000 00000000 00000000 00000000 00000013 00000000
> > > >  ---[ end trace 495200a78b24980e ]---
> > > >  random: fast init done
> > > >  [drm:drm_atomic_helper_wait_for_dependencies] *ERROR* [CRTC:46:crtc-0] flip_done timed out
> > > >  [drm:drm_atomic_helper_wait_for_dependencies] *ERROR* [CONNECTOR:48:DSI-1] flip_done timed out
> > > >  [drm:drm_atomic_helper_wait_for_dependencies] *ERROR* [PLANE:30:plane-0] flip_done timed out
> > > >
> > > > But the expected video start delay value is 513 which states that
> > > > the second parameter on the computation is "front porch" value
> > > > (no sync timings included).
> > > >
> > > > This is clearly confirmed from the legacy [1] and new [2] bsp codes
> > > > that the second parameter on the video start delay is "front porch"
> > > >
> > > > Here is the detailed evidence for calculating front porch as per
> > > > bsp code.
> > > >
> > > > vfp = panel->lcd_vt - panel->lcd_y - panel->lcd_vbp
> > > > => (panel->lcd_vt) - panel->lcd_y - panel->lcd_vbp
> > > > => (tt->ver_front_porch + lcdp->panel_info.lcd_vbp
> > > >     + lcdp->panel_info.lcd_y) -  panel->lcd_y - panel->lcd_vbp
> > > > => tt->ver_front_porch
> > >
> > > The comment on patch 1 still applies on this patch
> >
> > Thanks, I have responded on that. Same applies here.
>
> So this patch fixes the misinterpretation of Allwinner's back porch value,
> much like patch 1, but this one is for the vertical back porch. So I think
> you should follow the same advice I gave you for patch 1.

Yes, indeed I'm planning to do the same. thanks!

Patch
diff mbox series

diff --git a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
index b3ca85410b2c..47d571d97600 100644
--- a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
+++ b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
@@ -375,7 +375,7 @@  static u16 sun6i_dsi_get_video_start_delay(struct sun6i_dsi *dsi,
 	 * working in all supported panels as of now.
 	 */
 	u8 start = 1;
-	u16 delay = mode->vtotal - (mode->vsync_end - mode->vdisplay) + start;
+	u16 delay = mode->vtotal - (mode->vsync_start - mode->vdisplay) + start;
 
 	if (delay > mode->vtotal)
 		delay = delay % mode->vtotal;