On Thu, 2025-11-27 at 19:49 +0200, Imre Deak wrote:
> Factor out align_max_sink_dsc_input_bpp(), also used later for computing
> the maximum DSC input BPP limit.
>
> Signed-off-by: Imre Deak <[email protected]>
> ---
> drivers/gpu/drm/i915/display/intel_dp.c | 28 ++++++++++++++++---------
> 1 file changed, 18 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c
> b/drivers/gpu/drm/i915/display/intel_dp.c
> index 000fccc39a292..dcb9bc11e677b 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> @@ -1893,12 +1893,27 @@ int intel_dp_dsc_max_src_input_bpc(struct
> intel_display *display)
> return intel_dp_dsc_min_src_input_bpc();
> }
>
> +static int align_max_sink_dsc_input_bpp(const struct intel_connector
> *connector,
> + int max_pipe_bpp)
> +{
> + u8 dsc_bpc[3];
I think it's safer to use the '= {}' we had before, because that zeroes
the array, so in case of any stack leaks, you won't leak aleatory parts
of the memory. In this case it's only 3 bytes, so hardly anything
important could leak, but anyway.
Also, since this is 3 bytes long, it's theoretically better to have it
at the end of the stack declarations.
> + int num_bpc;
> + int i;
> +
> + num_bpc = drm_dp_dsc_sink_supported_input_bpcs(connector->dp.dsc_dpcd,
> + dsc_bpc);
> + for (i = 0; i < num_bpc; i++) {
> + if (dsc_bpc[i] * 3 <= max_pipe_bpp)
> + return dsc_bpc[i] * 3;
> + }
> +
> + return 0;
> +}
> +
> int intel_dp_dsc_compute_max_bpp(const struct intel_connector *connector,
> u8 max_req_bpc)
> {
> struct intel_display *display = to_intel_display(connector);
> - int i, num_bpc;
> - u8 dsc_bpc[3] = {};
> int dsc_max_bpc;
>
> dsc_max_bpc = intel_dp_dsc_max_src_input_bpc(display);
> @@ -1908,14 +1923,7 @@ int intel_dp_dsc_compute_max_bpp(const struct
> intel_connector *connector,
>
> dsc_max_bpc = min(dsc_max_bpc, max_req_bpc);
>
> - num_bpc = drm_dp_dsc_sink_supported_input_bpcs(connector->dp.dsc_dpcd,
> - dsc_bpc);
> - for (i = 0; i < num_bpc; i++) {
> - if (dsc_max_bpc >= dsc_bpc[i])
> - return dsc_bpc[i] * 3;
> - }
> -
> - return 0;
> + return align_max_sink_dsc_input_bpp(connector, dsc_max_bpc * 3);
> }
>
> static int intel_dp_source_dsc_version_minor(struct intel_display *display)
