On Thu, 07 Aug 2025, Jani Nikula <jani.nik...@linux.intel.com> wrote: > On Thu, 07 Aug 2025, Ankit Nautiyal <ankit.k.nauti...@intel.com> wrote: >> Add a drm_WARN_ON() in intel_crtc_init() to catch cases where >> crtc->num_scalers exceeds the expected SKL_NUM_SCALERS limit. >> >> This condition should not occur, as the number of scalers per pipe does not >> exceed two for current platforms, making SKL_NUM_SCALERS (2) a safer upper >> limit. However, if a platform ever gains more scalers per pipe than >> SKL_NUM_SCALERS, it could lead to issues when crtc->num_scalers is used to >> iterate over scaler_state->scalers. >> >> To prevent this, warn and clamp the value to SKL_NUM_SCALERS. >> >> Suggested-by: Jani Nikula <jani.nik...@intel.com> >> Signed-off-by: Ankit Nautiyal <ankit.k.nauti...@intel.com> > > Reviewed-by: Jani Nikula <jani.nik...@intel.com>
PS. This could've been in __intel_display_device_info_runtime_init() too, but no big deal. > >> --- >> drivers/gpu/drm/i915/display/intel_crtc.c | 3 +++ >> 1 file changed, 3 insertions(+) >> >> diff --git a/drivers/gpu/drm/i915/display/intel_crtc.c >> b/drivers/gpu/drm/i915/display/intel_crtc.c >> index a187db6df2d3..e262e686dc2b 100644 >> --- a/drivers/gpu/drm/i915/display/intel_crtc.c >> +++ b/drivers/gpu/drm/i915/display/intel_crtc.c >> @@ -317,6 +317,9 @@ int intel_crtc_init(struct intel_display *display, enum >> pipe pipe) >> crtc->pipe = pipe; >> crtc->num_scalers = DISPLAY_RUNTIME_INFO(display)->num_scalers[pipe]; >> >> + if (drm_WARN_ON(display->drm, crtc->num_scalers > SKL_NUM_SCALERS)) >> + crtc->num_scalers = SKL_NUM_SCALERS; >> + >> if (DISPLAY_VER(display) >= 9) >> primary = skl_universal_plane_create(display, pipe, PLANE_1); >> else -- Jani Nikula, Intel
