Re: [Intel-gfx] [PATCH v2 6/7] drm/i915: No 10bit gamma on desktop gen3 parts

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

On Thu, May 25, 2023 at 09:25:46PM +0000, Shankar, Uma wrote:
> 
> 
> > -----Original Message-----
> > From: Intel-gfx <intel-gfx-bounces@lists.freedesktop.org> On Behalf Of Ville Syrjala
> > Sent: Thursday, April 13, 2023 10:19 PM
> > To: intel-gfx@lists.freedesktop.org
> > Cc: dri-devel@lists.freedesktop.org
> > Subject: [Intel-gfx] [PATCH v2 6/7] drm/i915: No 10bit gamma on desktop gen3 parts
> > 
> > From: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > 
> > Apparently desktop gen3 parts don't support the 10bit gamma mode at all. Stop
> > claiming otherwise.
> > 
> > As is the case with pipe A on gen3 mobile parts, the PIPECONF gamma mode bit can
> > be set but it has no effect on the output.
> > 
> > PNV seems to be the only slight exception, but generally the desktop PNV variant
> > looks more like a mobile part so this is not entirely surprising.
> 
> Couldn't check the relevant spec to re-confirm, trusting your judgment here.

The spec isn't helpful here actually. Real world testing on every
gen3 platform was needed to be sure how this works.

> Reviewed-by: Uma Shankar <uma.shankar@intel.com>

Thanks.

> 
> > Fixes: 67630bacae23 ("drm/i915: Add 10bit gamma mode for gen2/3")
> > Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > ---
> >  drivers/gpu/drm/i915/i915_pci.c | 8 +++++++-
> >  1 file changed, 7 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/i915_pci.c b/drivers/gpu/drm/i915/i915_pci.c index
> > cddb6e197972..305c05c3f93b 100644
> > --- a/drivers/gpu/drm/i915/i915_pci.c
> > +++ b/drivers/gpu/drm/i915/i915_pci.c
> > @@ -250,13 +250,13 @@ static const struct intel_device_info i865g_info = {
> >  	.dma_mask_size = 32, \
> >  	I9XX_PIPE_OFFSETS, \
> >  	I9XX_CURSOR_OFFSETS, \
> > -	I9XX_COLORS, \
> >  	GEN_DEFAULT_PAGE_SIZES, \
> >  	GEN_DEFAULT_REGIONS
> > 
> >  static const struct intel_device_info i915g_info = {
> >  	GEN3_FEATURES,
> >  	PLATFORM(INTEL_I915G),
> > +	I845_COLORS,
> >  	.has_coherent_ggtt = false,
> >  	.display.cursor_needs_physical = 1,
> >  	.display.has_overlay = 1,
> > @@ -268,6 +268,7 @@ static const struct intel_device_info i915g_info = {  static
> > const struct intel_device_info i915gm_info = {
> >  	GEN3_FEATURES,
> >  	PLATFORM(INTEL_I915GM),
> > +	I9XX_COLORS,
> >  	.is_mobile = 1,
> >  	.display.cursor_needs_physical = 1,
> >  	.display.has_overlay = 1,
> > @@ -281,6 +282,7 @@ static const struct intel_device_info i915gm_info = {  static
> > const struct intel_device_info i945g_info = {
> >  	GEN3_FEATURES,
> >  	PLATFORM(INTEL_I945G),
> > +	I845_COLORS,
> >  	.display.has_hotplug = 1,
> >  	.display.cursor_needs_physical = 1,
> >  	.display.has_overlay = 1,
> > @@ -292,6 +294,7 @@ static const struct intel_device_info i945g_info = {  static
> > const struct intel_device_info i945gm_info = {
> >  	GEN3_FEATURES,
> >  	PLATFORM(INTEL_I945GM),
> > +	I9XX_COLORS,
> >  	.is_mobile = 1,
> >  	.display.has_hotplug = 1,
> >  	.display.cursor_needs_physical = 1,
> > @@ -306,6 +309,7 @@ static const struct intel_device_info i945gm_info = {  static
> > const struct intel_device_info g33_info = {
> >  	GEN3_FEATURES,
> >  	PLATFORM(INTEL_G33),
> > +	I845_COLORS,
> >  	.display.has_hotplug = 1,
> >  	.display.has_overlay = 1,
> >  	.dma_mask_size = 36,
> > @@ -314,6 +318,7 @@ static const struct intel_device_info g33_info = {  static
> > const struct intel_device_info pnv_g_info = {
> >  	GEN3_FEATURES,
> >  	PLATFORM(INTEL_PINEVIEW),
> > +	I9XX_COLORS,
> >  	.display.has_hotplug = 1,
> >  	.display.has_overlay = 1,
> >  	.dma_mask_size = 36,
> > @@ -322,6 +327,7 @@ static const struct intel_device_info pnv_g_info = {  static
> > const struct intel_device_info pnv_m_info = {
> >  	GEN3_FEATURES,
> >  	PLATFORM(INTEL_PINEVIEW),
> > +	I9XX_COLORS,
> >  	.is_mobile = 1,
> >  	.display.has_hotplug = 1,
> >  	.display.has_overlay = 1,
> > --
> > 2.39.2
> 

-- 
Ville Syrjälä
Intel