| Message ID | 20241023065257.190035-7-ankit.k.nautiyal@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Add support for 3 VDSC engines 12 slices | expand |
> -----Original Message----- > From: Nautiyal, Ankit K <ankit.k.nautiyal@intel.com> > Sent: Wednesday, October 23, 2024 12:23 PM > To: intel-gfx@lists.freedesktop.org > Cc: intel-xe@lists.freedesktop.org; Kandpal, Suraj <suraj.kandpal@intel.com> > Subject: [PATCH 06/16] drm/i915/dp: Ensure hactive is divisible by slice count > > According to the DSC spec, the slice width should be chosen such that the > picture width (hactive) is evenly divisible by the slice width. > If not, extra pixels (padding) must be added to the last slice to ensure all slices > have the same width. > > Currently, we do not support handling these extra pixels. > Therefore, select a slice count that evenly divides the hactive (slice_width = > hactive / slice_count). > > This check is already implemented for DSI, where the slice count is selected > from the BIOS. > > For DP, currently with 1, 2, 4 slices per pipe it is unlikely to have slice count not > being able to divide hactive, but with 3 DSC engines and 3 slices, we can have > such cases. Adding this check prepares for future scenarios where such > configurations might be used. > > Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com> LGTM, Reviewed-by: Suraj Kandpal <suraj.kandpal@intel.com> > --- > drivers/gpu/drm/i915/display/intel_dp.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/drivers/gpu/drm/i915/display/intel_dp.c > b/drivers/gpu/drm/i915/display/intel_dp.c > index 77487a55280c..3b20ea844925 100644 > --- a/drivers/gpu/drm/i915/display/intel_dp.c > +++ b/drivers/gpu/drm/i915/display/intel_dp.c > @@ -1037,6 +1037,9 @@ u8 intel_dp_dsc_get_slice_count(const struct > intel_connector *connector, > if (num_joined_pipes > 1 && valid_dsc_slicecount[i] < 2) > continue; > > + if (mode_hdisplay % test_slice_count) > + continue; > + > if (min_slice_count <= test_slice_count) > return test_slice_count; > } > -- > 2.45.2
diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c index 77487a55280c..3b20ea844925 100644 --- a/drivers/gpu/drm/i915/display/intel_dp.c +++ b/drivers/gpu/drm/i915/display/intel_dp.c @@ -1037,6 +1037,9 @@ u8 intel_dp_dsc_get_slice_count(const struct intel_connector *connector, if (num_joined_pipes > 1 && valid_dsc_slicecount[i] < 2) continue; + if (mode_hdisplay % test_slice_count) + continue; + if (min_slice_count <= test_slice_count) return test_slice_count; }
According to the DSC spec, the slice width should be chosen such that the picture width (hactive) is evenly divisible by the slice width. If not, extra pixels (padding) must be added to the last slice to ensure all slices have the same width. Currently, we do not support handling these extra pixels. Therefore, select a slice count that evenly divides the hactive (slice_width = hactive / slice_count). This check is already implemented for DSI, where the slice count is selected from the BIOS. For DP, currently with 1, 2, 4 slices per pipe it is unlikely to have slice count not being able to divide hactive, but with 3 DSC engines and 3 slices, we can have such cases. Adding this check prepares for future scenarios where such configurations might be used. Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com> --- drivers/gpu/drm/i915/display/intel_dp.c | 3 +++ 1 file changed, 3 insertions(+)