On Tue, 17 Dec 2024, Ankit Nautiyal <ankit.k.nautiyal@xxxxxxxxx> wrote:
> Check for DSC support before computing link config with DSC.
> For DP MST we are already doing the same.
>
> Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@xxxxxxxxx>
> Reviewed-by: Suraj Kandpal <suraj.kandpal@xxxxxxxxx>
> ---
> drivers/gpu/drm/i915/display/intel_dp.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
> index 908b9887f89b..dd2da9facaad 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> @@ -2375,9 +2375,6 @@ int intel_dp_dsc_compute_config(struct intel_dp *intel_dp,
> intel_dp_supports_fec(intel_dp, connector, pipe_config) &&
> !intel_dp_is_uhbr(pipe_config));
>
> - if (!intel_dp_supports_dsc(intel_dp, connector, pipe_config))
> - return -EINVAL;
> -
> if (!intel_dp_dsc_supports_format(connector, pipe_config->output_format))
> return -EINVAL;
>
> @@ -2652,6 +2649,9 @@ intel_dp_compute_link_config(struct intel_encoder *encoder,
> str_yes_no(ret), str_yes_no(joiner_needs_dsc),
> str_yes_no(intel_dp->force_dsc_en));
>
> + if (!intel_dp_supports_dsc(intel_dp, connector, pipe_config))
> + return -EINVAL;
> +
The (pre-existing) problem with this is that we debug log we fall back
to DSC, while we don't.
Maybe we should do something like this instead, both in SST and MST code:
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -2644,6 +2644,11 @@ intel_dp_compute_link_config(struct intel_encoder *encoder,
dsc_needed = true;
}
+ if (dsc_needed && !intel_dp_supports_dsc(connector, pipe_config)) {
+ drm_dbg_kms(display->drm, "DSC required but not available.\n");
+ return -EINVAL;
+ }
+
if (dsc_needed) {
drm_dbg_kms(display->drm,
"Try DSC (fallback=%s, joiner=%s, force=%s)\n",
BR,
Jani.
> if (!intel_dp_compute_config_limits(intel_dp, pipe_config,
> respect_downstream_limits,
> true,
--
Jani Nikula, Intel
