Re: [PATCH i-g-t] tests/kms_cursor_legacy: Prefer tile4 modifier when supported

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

On Mon, Mar 16, 2026 at 05:27:15PM +0000, B, Jeevan wrote:
> > -----Original Message-----
> > From: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > Sent: Monday, March 16, 2026 8:15 PM
> > To: B, Jeevan <jeevan.b@intel.com>
> > Cc: igt-dev@lists.freedesktop.org; Naladala, Ramanaidu
> > <ramanaidu.naladala@intel.com>
> > Subject: Re: [PATCH i-g-t] tests/kms_cursor_legacy: Prefer tile4 modifier when
> > supported
> > 
> > On Mon, Mar 16, 2026 at 09:08:07AM +0530, Jeevan B wrote:
> > > While creating the framebuffer, prefer tile4 when it is supported
> > > instead of always using linear. Fall back to linear if tile4 is not
> > > available.
> > 
> > Why?
> On Xe platforms, using the linear modifier takes longer to prepare and submit a flip compared to tiled modifiers. 

So it's a hack due to to the shortcomings of the xe driver. Someone
should really fix the kernel side so we didn't need such hacks...

> On HRR panels, the available frame time is small, and this delay can cause flips to be submitted in the Evasion region, 
> leading to sequence mismatches.
> > 
> > >
> > > Signed-off-by: Jeevan B <jeevan.b@intel.com>
> > > ---
> > >  tests/kms_cursor_legacy.c | 10 ++++++++--
> > >  1 file changed, 8 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/tests/kms_cursor_legacy.c b/tests/kms_cursor_legacy.c
> > > index 5399ef481..4c4e477a1 100644
> > > --- a/tests/kms_cursor_legacy.c
> > > +++ b/tests/kms_cursor_legacy.c
> > > @@ -367,15 +367,21 @@ static void set_fb_on_crtc(igt_display_t
> > > *display, igt_crtc_t *crtc,  {
> > >  	drmModeModeInfoPtr mode;
> > >  	igt_plane_t *primary;
> > > +	uint64_t modifier = DRM_FORMAT_MOD_LINEAR;
> > >
> > >  	igt_output_set_crtc(output, crtc);
> > >  	mode = igt_output_get_mode(output);
> > >
> > > +	primary = igt_output_get_plane_type(output,
> > DRM_PLANE_TYPE_PRIMARY);
> > > +
> > > +	if (igt_plane_has_format_mod(primary, DRM_FORMAT_XRGB8888,
> > > +				     I915_FORMAT_MOD_4_TILED))
> > > +		modifier = I915_FORMAT_MOD_4_TILED;
> > > +
> > >  	igt_create_pattern_fb(display->drm_fd,
> > >  		      mode->hdisplay, mode->vdisplay,
> > > -		      DRM_FORMAT_XRGB8888, DRM_FORMAT_MOD_LINEAR,
> > fb_info);
> > > +		      DRM_FORMAT_XRGB8888, modifier, fb_info);
> > >
> > > -	primary = igt_output_get_plane_type(output,
> > DRM_PLANE_TYPE_PRIMARY);
> > >  	igt_plane_set_fb(primary, fb_info);
> > >  }
> > >
> > > --
> > > 2.43.0
> > 
> > --
> > Ville Syrjälä
> > Intel

-- 
Ville Syrjälä
Intel