Re: [PATCH v2] drm/i915: Fix drm:intel_enable_lvds ERROR message in kernel log

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

On Fri, Apr 20, 2018 at 01:36:40PM +0300, Jani Nikula wrote:
> On Thu, 19 Apr 2018, Ville Syrjala <ville.syrjala@linux.intel.com> wrote:
> > From: Florent Flament <contact@florentflament.com>
> >
> > Fix `[drm:intel_enable_lvds] *ERROR* timed out waiting for panel to
> > power on` in kernel log at boot time.
> >
> > Toshiba Satellite Z930 laptops needs between 1 and 2 seconds to power
> > on its screen during Intel i915 DRM initialization. This currently
> > results in a `[drm:intel_enable_lvds] *ERROR* timed out waiting for
> > panel to power on` message appearing in the kernel log during boot
> > time and when stopping the machine.
> >
> > This change increases the timeout of the `intel_enable_lvds` function
> > from 1 to 2 seconds, letting enough time for the Satellite 930 LCD
> > screen to power on, and suppressing the error message from the kernel
> > log.
> 
> Please update the commit message to match what the patch actually does
> now, instead of hiding it in braces below. With that (and can be done
> while pushing),
> 
> Reviewed-by: Jani Nikula <jani.nikula@intel.com>

Pushed to dinq with a slightly amended commit message. Also added
cc:stable.

Thanks for the original patch, and review.

> 
> 
> >
> > This patch has been successfully tested on Linux 4.14 running on a
> > Toshiba Satellite Z930.
> >
> > Signed-off-by: Florent Flament <contact@florentflament.com>
> > [vsyrjala: bump the timeout from 2 to 5 seconds to match the DP
> >  code and properly cover the max hw timeout of ~4 seconds, and
> >  drop the comment about the specific machine since this is not
> >  a particulary surprising issue, nor specific to that one machine]
> > Cc: Pavel Petrovic <ppetrovic@acm.org>
> > Cc: Sérgio M. Basto <sergio@serjux.com>
> > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=103414
> > References: https://bugzilla.kernel.org/show_bug.cgi?id=57591
> > Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > ---
> >  drivers/gpu/drm/i915/intel_lvds.c | 3 ++-
> >  1 file changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/gpu/drm/i915/intel_lvds.c b/drivers/gpu/drm/i915/intel_lvds.c
> > index d35d2d50f595..8691c86f579c 100644
> > --- a/drivers/gpu/drm/i915/intel_lvds.c
> > +++ b/drivers/gpu/drm/i915/intel_lvds.c
> > @@ -326,7 +326,8 @@ static void intel_enable_lvds(struct intel_encoder *encoder,
> >  
> >  	I915_WRITE(PP_CONTROL(0), I915_READ(PP_CONTROL(0)) | PANEL_POWER_ON);
> >  	POSTING_READ(lvds_encoder->reg);
> > -	if (intel_wait_for_register(dev_priv, PP_STATUS(0), PP_ON, PP_ON, 1000))
> > +
> > +	if (intel_wait_for_register(dev_priv, PP_STATUS(0), PP_ON, PP_ON, 5000))
> >  		DRM_ERROR("timed out waiting for panel to power on\n");
> >  
> >  	intel_panel_enable_backlight(pipe_config, conn_state);
> 
> -- 
> Jani Nikula, Intel Open Source Technology Center

-- 
Ville Syrjälä
Intel
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