Re: [PATCH v4] drm/i915/edp: Add a T12 panel delay quirk to fix DP AUX CH timeouts

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Wed, Jul 05, 2017 at 06:25:30PM +0000, Navare, Manasi D wrote:
> On Fri, Jun 30, 2017 at 09:33:48AM -0700, Manasi Navare wrote:
> > This patch fixes the DP AUX CH timeouts observed during CI IGT tests 
> > thus fixing the CI failures. This is done by adding a quirk for a 
> > particular PCI device that requires the panel power cycle delay (T12) 
> > to be set to 800ms which is 300msecs more than the minimum value 
> > specified in the eDP spec. So a quirk is implemented for that specific 
> > PCI device.
> > 
> > v4:
> > * Add Bugzilla links for FDO bugs in the commit message (Ville, Jani)
> > v3:
> > * Change some comments, specify the delay as 800 * 10 (Ville)
> > v2:
> > * Change the function and variable names to from PPS_T12_ to _T12 
> > since it is a T12 delay (Clint)
> > 
> > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=101144
> > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=101154
> > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=101167
> > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=101515
> > Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
> > Cc: Clinton Taylor <clinton.a.taylor@intel.com>
> > Signed-off-by: Manasi Navare <manasi.d.navare@intel.com>
> > Reviewed-by: Clinton Taylor <clinton.a.taylor@intel.com>
> > Acked-by: Ville Syrjala <ville.syrjala@linux.intel.com>
> 
> I don't recall ever stating that explicitly. Please don't invent acks/rbs.
> 
> You had said "Looks good to me" on the previous version.  Doesn't that mean its Acked By you?

I don't generally expect acks/rbs to appear on a patch unless explicitly
stated. I guess sometimes it might be an irc 'ack' or something like
that, but that's as far as I would go in interpreting things.

> 
> 
> I also fixed up a checkpatch warning about an empty line being present where none was supposed to be. Please review all checkpatch warnings when submitting patches.
> 
> Thanks for fixing this, sorry must have missed this while respinning. Else I always have been checking for checkpatch
> Warnings.
> 
> Manasi
> 
> Anyways this is now pushed to dinq. Thanks for the patch.
> 
> > ---
> >  drivers/gpu/drm/i915/i915_drv.h      |  1 +
> >  drivers/gpu/drm/i915/intel_display.c | 14 ++++++++++++++
> >  drivers/gpu/drm/i915/intel_dp.c      | 11 +++++++++++
> >  3 files changed, 26 insertions(+)
> > 
> > diff --git a/drivers/gpu/drm/i915/i915_drv.h 
> > b/drivers/gpu/drm/i915/i915_drv.h index effbe4f..4bef5d3 100644
> > --- a/drivers/gpu/drm/i915/i915_drv.h
> > +++ b/drivers/gpu/drm/i915/i915_drv.h
> > @@ -1167,6 +1167,7 @@ enum intel_sbi_destination {  #define 
> > QUIRK_INVERT_BRIGHTNESS (1<<2)  #define QUIRK_BACKLIGHT_PRESENT (1<<3)  
> > #define QUIRK_PIN_SWIZZLED_PAGES (1<<5)
> > +#define QUIRK_INCREASE_T12_DELAY (1<<6)
> >  
> >  struct intel_fbdev;
> >  struct intel_fbc_work;
> > diff --git a/drivers/gpu/drm/i915/intel_display.c 
> > b/drivers/gpu/drm/i915/intel_display.c
> > index 4e03ca6..87dfde9 100644
> > --- a/drivers/gpu/drm/i915/intel_display.c
> > +++ b/drivers/gpu/drm/i915/intel_display.c
> > @@ -14765,6 +14765,17 @@ static void quirk_backlight_present(struct drm_device *dev)
> >  	DRM_INFO("applying backlight present quirk\n");  }
> >  
> > +/* Toshiba Satellite P50-C-18C requires T12 delay to be min 800ms
> > + * which is 300 ms greater than eDP spec T12 min.
> > + */
> > +static void quirk_increase_t12_delay(struct drm_device *dev) {
> > +	struct drm_i915_private *dev_priv = to_i915(dev);
> > +
> > +	dev_priv->quirks |= QUIRK_INCREASE_T12_DELAY;
> > +	DRM_INFO("Applying T12 delay quirk\n"); }
> > +
> >  struct intel_quirk {
> >  	int device;
> >  	int subsystem_vendor;
> > @@ -14848,6 +14859,9 @@ static struct intel_quirk intel_quirks[] = {
> >  
> >  	/* Dell Chromebook 11 (2015 version) */
> >  	{ 0x0a16, 0x1028, 0x0a35, quirk_backlight_present },
> > +
> > +	/* Toshiba Satellite P50-C-18C */
> > +	{ 0x191B, 0x1179, 0xF840, quirk_increase_t12_delay },
> >  };
> >  
> >  static void intel_init_quirks(struct drm_device *dev) diff --git 
> > a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c 
> > index 67bc8a7a..538950c 100644
> > --- a/drivers/gpu/drm/i915/intel_dp.c
> > +++ b/drivers/gpu/drm/i915/intel_dp.c
> > @@ -5230,6 +5230,17 @@ intel_dp_init_panel_power_sequencer(struct drm_device *dev,
> >  	intel_pps_dump_state("cur", &cur);
> >  
> >  	vbt = dev_priv->vbt.edp.pps;
> > +	/* On Toshiba Satellite P50-C-18C system the VBT T12 delay
> > +	 * of 500ms appears to be too short. Ocassionally the panel
> > +	 * just fails to power back on. Increasing the delay to 800ms
> > +	 * seems sufficient to avoid this problem.
> > +	 */
> > +	if (dev_priv->quirks & QUIRK_INCREASE_T12_DELAY) {
> > +
> > +		vbt.t11_t12 = max_t(u16, vbt.t11_t12, 800 * 10);
> > +		DRM_DEBUG_KMS("Increasing T12 panel delay as per the quirk to %d\n",
> > +			      vbt.t11_t12);
> > +	}
> >  	/* T11_T12 delay is special and actually in units of 100ms, but zero
> >  	 * based in the hw (so we need to add 100 ms). But the sw vbt
> >  	 * table multiplies it with 1000 to make it in units of 100usec,
> > --
> > 2.1.4
> 
> --
> Ville Syrjälä
> Intel OTC

-- 
Ville Syrjälä
Intel OTC
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