| Message ID | 1870321.D0AfKTtRus@dhcp89 (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tue, Mar 26, 2013 at 4:40 PM, Michal Srb <msrb@suse.com> wrote: > Since 2514bc510d0c3aadcc5204056bb440fa36845147, the intel_dp_mode_fixup > function prefers lane count over frequency. That causes problems on > hardware that has less working lanes than it reports. This option allows > to workaround such hardware bugs. > > Signed-off-by: Michal Srb <msrb@suse.com> > --- > This is workaround for hardware issues uncovered by this commit: > > commit 2514bc510d0c3aadcc5204056bb440fa36845147 > Author: Jesse Barnes <jbarnes@virtuousgeek.org> > Date: Thu Jun 21 15:13:50 2012 -0700 > > drm/i915: prefer wide & slow to fast & narrow in DP configs > > High frequency link configurations have the potential to cause trouble > with long and/or cheap cables, so prefer slow and wide configurations > instead. This patch has the potential to cause trouble for eDP > configurations that lie about available lanes, so if we run into that we > can make it conditional on eDP. > > I have IBM POS machine (4852-570 Truman) that has internal monitor > connected over display port. It reports to have 2 lanes, but only 1 > lane works reliably. With 2 lanes used, the monitor sometimes doesn't > turn on. It seems that this is hardware issue specific for this model. > > From discussion that was around the 2514bc510d0c3aadcc5204056bb440fa36845147 > commit I understand there are more machines that have similar problems. > This option can be used to solve them. It sounds like we need to start with a DPCD quirk database ... Ajax? -Daniel > --- > > drivers/gpu/drm/i915/i915_drv.c | 6 ++++++ > drivers/gpu/drm/i915/i915_drv.h | 1 + > drivers/gpu/drm/i915/intel_dp.c | 15 +++++++++++++-- > 3 files changed, 20 insertions(+), 2 deletions(-) > > diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c > index 6c4b13c..5949d7c 100644 > --- a/drivers/gpu/drm/i915/i915_drv.c > +++ b/drivers/gpu/drm/i915/i915_drv.c > @@ -123,6 +123,12 @@ module_param_named(preliminary_hw_support, > i915_preliminary_hw_support, int, 060 > MODULE_PARM_DESC(preliminary_hw_support, > "Enable preliminary hardware support. (default: false)"); > > +int i915_dp_limit_max_lane_count __read_mostly = -1; > +module_param_named(dp_limit_max_lane_count, i915_dp_limit_max_lane_count, > int, 0600); > +MODULE_PARM_DESC(dp_limit_max_lane_count, > + "Limit the maximal number of used display port lanes. " > + "(default: -1 (no limit))"); > + > static struct drm_driver driver; > extern int intel_agp_enabled; > > diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h > index 1657d873..646e400 100644 > --- a/drivers/gpu/drm/i915/i915_drv.h > +++ b/drivers/gpu/drm/i915/i915_drv.h > @@ -1398,6 +1398,7 @@ extern int i915_enable_fbc __read_mostly; > extern bool i915_enable_hangcheck __read_mostly; > extern int i915_enable_ppgtt __read_mostly; > extern unsigned int i915_preliminary_hw_support __read_mostly; > +extern int i915_dp_limit_max_lane_count __read_mostly; > > extern int i915_suspend(struct drm_device *dev, pm_message_t state); > extern int i915_resume(struct drm_device *dev); > diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c > index 662a185..3812773 100644 > --- a/drivers/gpu/drm/i915/intel_dp.c > +++ b/drivers/gpu/drm/i915/intel_dp.c > @@ -132,6 +132,17 @@ intel_edp_target_clock(struct intel_encoder > *intel_encoder, > return mode->clock; > } > > +static inline u8 > +intel_dp_max_lane_count(u8 dpcd[DP_RECEIVER_CAP_SIZE]) > +{ > + u8 max_lane_count = drm_dp_max_lane_count(dpcd); > + > + if(i915_dp_limit_max_lane_count != -1 && max_lane_count > > i915_dp_limit_max_lane_count) > + max_lane_count = i915_dp_limit_max_lane_count; > + > + return max_lane_count; > +} > + > static int > intel_dp_max_link_bw(struct intel_dp *intel_dp) > { > @@ -184,7 +195,7 @@ intel_dp_adjust_dithering(struct intel_dp *intel_dp, > { > int max_link_clock = > drm_dp_bw_code_to_link_rate(intel_dp_max_link_bw(intel_dp)); > - int max_lanes = drm_dp_max_lane_count(intel_dp->dpcd); > + int max_lanes = intel_dp_max_lane_count(intel_dp->dpcd); > int max_rate, mode_rate; > > mode_rate = intel_dp_link_required(mode->clock, 24); > @@ -697,7 +708,7 @@ intel_dp_mode_fixup(struct drm_encoder *encoder, > struct intel_dp *intel_dp = enc_to_intel_dp(encoder); > struct intel_connector *intel_connector = intel_dp->attached_connector; > int lane_count, clock; > - int max_lane_count = drm_dp_max_lane_count(intel_dp->dpcd); > + int max_lane_count = intel_dp_max_lane_count(intel_dp->dpcd); > int max_clock = intel_dp_max_link_bw(intel_dp) == DP_LINK_BW_2_7 ? 1 : 0; > int bpp, mode_rate; > static int bws[2] = { DP_LINK_BW_1_62, DP_LINK_BW_2_7 }; > -- > 1.7.7 > > > _______________________________________________ > Intel-gfx mailing list > Intel-gfx@lists.freedesktop.org > http://lists.freedesktop.org/mailman/listinfo/intel-gfx
On Tuesday 26 of March 2013 16:49:30 Daniel Vetter wrote: > On Tue, Mar 26, 2013 at 4:40 PM, Michal Srb <msrb@suse.com> wrote: > > I have IBM POS machine (4852-570 Truman) that has internal monitor > > connected over display port. It reports to have 2 lanes, but only 1 > > lane works reliably. With 2 lanes used, the monitor sometimes doesn't > > turn on. It seems that this is hardware issue specific for this model. > > > > From discussion that was around the > > 2514bc510d0c3aadcc5204056bb440fa36845147 commit I understand there are > > more machines that have similar problems. This option can be used to > > solve them. > > It sounds like we need to start with a DPCD quirk database ... Ajax? > -Daniel Any update? DPCD of this monitor is 10 0a 82 40 00 00 01 00 02 00 00 00 10 01 00 by the way. Is the i915.dp_limit_max_lane_count unacceptable even as temporary workaround? Michal Srb
diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c index 6c4b13c..5949d7c 100644 --- a/drivers/gpu/drm/i915/i915_drv.c +++ b/drivers/gpu/drm/i915/i915_drv.c @@ -123,6 +123,12 @@ module_param_named(preliminary_hw_support, i915_preliminary_hw_support, int, 060 MODULE_PARM_DESC(preliminary_hw_support, "Enable preliminary hardware support. (default: false)"); +int i915_dp_limit_max_lane_count __read_mostly = -1; +module_param_named(dp_limit_max_lane_count, i915_dp_limit_max_lane_count, int, 0600); +MODULE_PARM_DESC(dp_limit_max_lane_count, + "Limit the maximal number of used display port lanes. " + "(default: -1 (no limit))"); + static struct drm_driver driver; extern int intel_agp_enabled; diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h index 1657d873..646e400 100644 --- a/drivers/gpu/drm/i915/i915_drv.h +++ b/drivers/gpu/drm/i915/i915_drv.h @@ -1398,6 +1398,7 @@ extern int i915_enable_fbc __read_mostly; extern bool i915_enable_hangcheck __read_mostly; extern int i915_enable_ppgtt __read_mostly; extern unsigned int i915_preliminary_hw_support __read_mostly; +extern int i915_dp_limit_max_lane_count __read_mostly; extern int i915_suspend(struct drm_device *dev, pm_message_t state); extern int i915_resume(struct drm_device *dev); diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c index 662a185..3812773 100644 --- a/drivers/gpu/drm/i915/intel_dp.c +++ b/drivers/gpu/drm/i915/intel_dp.c @@ -132,6 +132,17 @@ intel_edp_target_clock(struct intel_encoder *intel_encoder, return mode->clock; } +static inline u8 +intel_dp_max_lane_count(u8 dpcd[DP_RECEIVER_CAP_SIZE]) +{ + u8 max_lane_count = drm_dp_max_lane_count(dpcd); + + if(i915_dp_limit_max_lane_count != -1 && max_lane_count > i915_dp_limit_max_lane_count) + max_lane_count = i915_dp_limit_max_lane_count; + + return max_lane_count; +} + static int
Since 2514bc510d0c3aadcc5204056bb440fa36845147, the intel_dp_mode_fixup function prefers lane count over frequency. That causes problems on hardware that has less working lanes than it reports. This option allows to workaround such hardware bugs. Signed-off-by: Michal Srb <msrb@suse.com> --- This is workaround for hardware issues uncovered by this commit: commit 2514bc510d0c3aadcc5204056bb440fa36845147 Author: Jesse Barnes <jbarnes@virtuousgeek.org> Date: Thu Jun 21 15:13:50 2012 -0700 drm/i915: prefer wide & slow to fast & narrow in DP configs High frequency link configurations have the potential to cause trouble with long and/or cheap cables, so prefer slow and wide configurations instead. This patch has the potential to cause trouble for eDP configurations that lie about available lanes, so if we run into that we can make it conditional on eDP. I have IBM POS machine (4852-570 Truman) that has internal monitor connected over display port. It reports to have 2 lanes, but only 1 lane works reliably. With 2 lanes used, the monitor sometimes doesn't turn on. It seems that this is hardware issue specific for this model. From discussion that was around the 2514bc510d0c3aadcc5204056bb440fa36845147 commit I understand there are more machines that have similar problems. This option can be used to solve them. --- drivers/gpu/drm/i915/i915_drv.c | 6 ++++++ drivers/gpu/drm/i915/i915_drv.h | 1 + drivers/gpu/drm/i915/intel_dp.c | 15 +++++++++++++-- 3 files changed, 20 insertions(+), 2 deletions(-) intel_dp_max_link_bw(struct intel_dp *intel_dp) { @@ -184,7 +195,7 @@ intel_dp_adjust_dithering(struct intel_dp *intel_dp, { int max_link_clock = drm_dp_bw_code_to_link_rate(intel_dp_max_link_bw(intel_dp)); - int max_lanes = drm_dp_max_lane_count(intel_dp->dpcd); + int max_lanes = intel_dp_max_lane_count(intel_dp->dpcd); int max_rate, mode_rate; mode_rate = intel_dp_link_required(mode->clock, 24); @@ -697,7 +708,7 @@ intel_dp_mode_fixup(struct drm_encoder *encoder, struct intel_dp *intel_dp = enc_to_intel_dp(encoder); struct intel_connector *intel_connector = intel_dp->attached_connector; int lane_count, clock; - int max_lane_count = drm_dp_max_lane_count(intel_dp->dpcd); + int max_lane_count = intel_dp_max_lane_count(intel_dp->dpcd); int max_clock = intel_dp_max_link_bw(intel_dp) == DP_LINK_BW_2_7 ? 1 : 0; int bpp, mode_rate; static int bws[2] = { DP_LINK_BW_1_62, DP_LINK_BW_2_7 };