[Intel-gfx] [PATCH 2/5] drm/i915: Do not read GAMMA_MODE register
matthew.d.roper at intel.com
Tue Feb 23 18:16:19 UTC 2016
On Tue, Feb 23, 2016 at 10:36:36AM +0000, Lionel Landwerlin wrote:
> On 23/02/16 00:38, Matt Roper wrote:
> >On Mon, Feb 22, 2016 at 02:18:08PM +0000, Lionel Landwerlin wrote:
> >>Implement Daniel Stone's recommendation to not read registers to infer
> >>the hardware's state.
> >>Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin at intel.com>
> >Do we need to ensure that software and hardware state are synchronized
> >at startup? A boot firmware might have set it to something different
> >before our driver starts up; if we use 'fastboot' then we might not do
> >any modesets and might wind up with 0 (8BIT) in our state variable, but
> >something else actually programmed into the hardware.
> Thanks Matt,
> It makes sense know, I couldn't understand why this would ever be at
> something different that 8bit mode...
> I guess the value should be read from the intel_color_init()
> function upon startup.
We have a hardware state readout where we reconstruct the hardware state
for various things like plane state and such; you could add color
management readout to that. Alternatively, we could just force
known-good values into the hardware at startup as we do (or will very
soon) for stuff we don't trust the BIOS to get right like watermarks.
Graphics Software Engineer
IoTG Platform Enabling & Development
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