Re: [Intel-gfx] [PATCH 1/2] drm/i915: Do a dummy DPCD read before the actual read

2014-10-24 Thread Ville Syrjälä
On Thu, Oct 16, 2014 at 12:39:29PM -0700, Todd Previte wrote: > > On 10/16/2014 10:46 AM, ville.syrj...@linux.intel.com wrote: > > From: Ville Syrjälä > > > > Sometimes we seem to get utter garbage from DPCD reads. The resulting > > buffer is filled with the same byte, and the operation completed

Re: [Intel-gfx] [PATCH 1/2] drm/i915: Do a dummy DPCD read before the actual read

2014-10-21 Thread Daniel Vetter
On Thu, Oct 16, 2014 at 12:39:29PM -0700, Todd Previte wrote: > > On 10/16/2014 10:46 AM, ville.syrj...@linux.intel.com wrote: > >From: Ville Syrjälä > > > >Sometimes we seem to get utter garbage from DPCD reads. The resulting > >buffer is filled with the same byte, and the operation completed wi

Re: [Intel-gfx] [PATCH 1/2] drm/i915: Do a dummy DPCD read before the actual read

2014-10-17 Thread Todd Previte
On 10/17/2014 1:59 AM, Ville Syrjälä wrote: On Fri, Oct 17, 2014 at 11:43:21AM +0300, Jani Nikula wrote: On Thu, 16 Oct 2014, ville.syrj...@linux.intel.com wrote: From: Ville Syrjälä Sometimes we seem to get utter garbage from DPCD reads. The resulting buffer is filled with the same byte, an

Re: [Intel-gfx] [PATCH 1/2] drm/i915: Do a dummy DPCD read before the actual read

2014-10-17 Thread Todd Previte
On 10/17/2014 2:06 AM, Ville Syrjälä wrote: On Thu, Oct 16, 2014 at 12:39:29PM -0700, Todd Previte wrote: On 10/16/2014 10:46 AM, ville.syrj...@linux.intel.com wrote: From: Ville Syrjälä Sometimes we seem to get utter garbage from DPCD reads. The resulting buffer is filled with the same byte

Re: [Intel-gfx] [PATCH 1/2] drm/i915: Do a dummy DPCD read before the actual read

2014-10-17 Thread Todd Previte
On 10/17/2014 1:43 AM, Jani Nikula wrote: On Thu, 16 Oct 2014, ville.syrj...@linux.intel.com wrote: From: Ville Syrjälä Sometimes we seem to get utter garbage from DPCD reads. The resulting buffer is filled with the same byte, and the operation completed without errors. My HP ZR24w monitor se

Re: [Intel-gfx] [PATCH 1/2] drm/i915: Do a dummy DPCD read before the actual read

2014-10-17 Thread Ville Syrjälä
On Fri, Oct 17, 2014 at 11:43:21AM +0300, Jani Nikula wrote: > On Thu, 16 Oct 2014, ville.syrj...@linux.intel.com wrote: > > From: Ville Syrjälä > > > > Sometimes we seem to get utter garbage from DPCD reads. The resulting > > buffer is filled with the same byte, and the operation completed withou

Re: [Intel-gfx] [PATCH 1/2] drm/i915: Do a dummy DPCD read before the actual read

2014-10-17 Thread Jani Nikula
On Thu, 16 Oct 2014, ville.syrj...@linux.intel.com wrote: > From: Ville Syrjälä > > Sometimes we seem to get utter garbage from DPCD reads. The resulting > buffer is filled with the same byte, and the operation completed without > errors. My HP ZR24w monitor seems particularly susceptible to this

Re: [Intel-gfx] [PATCH 1/2] drm/i915: Do a dummy DPCD read before the actual read

2014-10-16 Thread Todd Previte
On 10/16/2014 10:46 AM, ville.syrj...@linux.intel.com wrote: From: Ville Syrjälä Sometimes we seem to get utter garbage from DPCD reads. The resulting buffer is filled with the same byte, and the operation completed without errors. My HP ZR24w monitor seems particularly susceptible to this pro

[Intel-gfx] [PATCH 1/2] drm/i915: Do a dummy DPCD read before the actual read

2014-10-16 Thread ville . syrjala
From: Ville Syrjälä Sometimes we seem to get utter garbage from DPCD reads. The resulting buffer is filled with the same byte, and the operation completed without errors. My HP ZR24w monitor seems particularly susceptible to this problem once it's gone into a sleep mode. The issue seems to happe