[PATCH] drm/i915/display: Don't allow tile4 framebuffer to do hflip on Xe2

[Juha-Pekka Heikkila]

On 12.9.2024 22.50, Matt Roper wrote:
> On Thu, Sep 12, 2024 at 05:46:06PM +0300, Juha-Pekka Heikkila wrote:
>> On Intel Xe2 hw tile4 is not supported with horizontal flip
>>
>> bspec 69853
> 
> The notes on this page seem to say that, but there's also bspec 68904
> which seems to have two two conflicting statements that apply to Xe2:
> 
>          "Horizontal flip (mirror the image from right to left) supported
>          with tile modes other than linear."
> 
> implies this _is_ supported for Tile4 (and TileX), but immediately below
> that,
> 
>          "Horizontal flip (mirror the image from right to left) is not
>          supported with tile mode of Tile4.  Horizontal flip (mirror the
>          image from right to left) is supported with tile mode of
>          linear."
> 
> says pretty much the opposite for Tile4 and linear.
> 
> It might be worth explicitly confirming this with the hardware guys and
> getting them to re-visit the tagging of these bspec pages to avoid the
> conflicting information.
> 

Thanks Matt, I think I'll need to start to bother hw guys with this 
issue to get clarity. Lucas also pointed this is not a limitation on BMG 
but I see LNL and BMG failing same way even if one is display 20 and 
other is display 14 .. and MTL display 14 does work with hflip + tile4.

/Juha-Pekka

> 
>>
>> Signed-off-by: Juha-Pekka Heikkila <juhapekka.heikkila at gmail.com>
>> ---
>>   drivers/gpu/drm/i915/display/intel_fb.c            | 13 +++++++++++++
>>   drivers/gpu/drm/i915/display/intel_fb.h            |  1 +
>>   drivers/gpu/drm/i915/display/skl_universal_plane.c | 12 ++++++++++++
>>   3 files changed, 26 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/i915/display/intel_fb.c b/drivers/gpu/drm/i915/display/intel_fb.c
>> index d2ff21e98545..c9038d239eb2 100644
>> --- a/drivers/gpu/drm/i915/display/intel_fb.c
>> +++ b/drivers/gpu/drm/i915/display/intel_fb.c
>> @@ -439,6 +439,19 @@ bool intel_fb_needs_64k_phys(u64 modifier)
>>   				      INTEL_PLANE_CAP_NEED64K_PHYS);
>>   }
>>   
>> +/**
>> + * intel_fb_is_tile4_modifier: Check if a modifier is a tile4 modifier type
>> + * @modifier: Modifier to check
>> + *
>> + * Returns:
>> + * Returns %true if @modifier is a tile4 modifier.
>> + */
>> +bool intel_fb_is_tile4_modifier(u64 modifier)
>> +{
>> +	return plane_caps_contain_any(lookup_modifier(modifier)->plane_caps,
>> +				      INTEL_PLANE_CAP_TILING_4);
>> +}
>> +
>>   static bool check_modifier_display_ver_range(const struct intel_modifier_desc *md,
>>   					     u8 display_ver_from, u8 display_ver_until)
>>   {
>> diff --git a/drivers/gpu/drm/i915/display/intel_fb.h b/drivers/gpu/drm/i915/display/intel_fb.h
>> index 068f3aee99aa..bff87994cf2c 100644
>> --- a/drivers/gpu/drm/i915/display/intel_fb.h
>> +++ b/drivers/gpu/drm/i915/display/intel_fb.h
>> @@ -35,6 +35,7 @@ bool intel_fb_is_ccs_modifier(u64 modifier);
>>   bool intel_fb_is_rc_ccs_cc_modifier(u64 modifier);
>>   bool intel_fb_is_mc_ccs_modifier(u64 modifier);
>>   bool intel_fb_needs_64k_phys(u64 modifier);
>> +bool intel_fb_is_tile4_modifier(u64 modifier);
>>   
>>   bool intel_fb_is_ccs_aux_plane(const struct drm_framebuffer *fb, int color_plane);
>>   int intel_fb_rc_ccs_cc_plane(const struct drm_framebuffer *fb);
>> diff --git a/drivers/gpu/drm/i915/display/skl_universal_plane.c b/drivers/gpu/drm/i915/display/skl_universal_plane.c
>> index 17d4c880ecc4..4de41ab5060a 100644
>> --- a/drivers/gpu/drm/i915/display/skl_universal_plane.c
>> +++ b/drivers/gpu/drm/i915/display/skl_universal_plane.c
>> @@ -1591,6 +1591,18 @@ static int skl_plane_check_fb(const struct intel_crtc_state *crtc_state,
>>   		return -EINVAL;
>>   	}
>>   
>> +	/*
>> +	 * Starting with LNL and BMG tile4 hflip is not supported
>> +	 */
>> +	if (rotation & DRM_MODE_REFLECT_X &&
>> +	    intel_fb_is_tile4_modifier(fb->modifier) &&
>> +	    ((DISPLAY_VER(dev_priv) >= 14 && IS_DGFX(dev_priv)) ||
>> +	     (DISPLAY_VER(dev_priv) >= 20 && !IS_DGFX(dev_priv)))) {
>> +		drm_dbg_kms(&dev_priv->drm,
>> +			    "horizontal flip is not supported with tile4 surface formats\n");
>> +		return -EINVAL;
>> +	}
>> +
>>   	if (drm_rotation_90_or_270(rotation)) {
>>   		if (!intel_fb_supports_90_270_rotation(to_intel_framebuffer(fb))) {
>>   			drm_dbg_kms(&dev_priv->drm,
>> -- 
>> 2.45.2
>>
>