Re: [PATCH v3 08/10] drm/msm/dsi: Account for DSC's bits_per_pixel having 4 fractional bits

[Dmitry Baryshkov]

On 09/10/2022 21:53, Marijn Suijten wrote:
> drm_dsc_config's bits_per_pixel field holds a fractional value with 4
> bits, which all panel drivers should adhere to for
> drm_dsc_pps_payload_pack() to generate a valid payload.  All code in the
> DSI driver here seems to assume that this field doesn't contain any
> fractional bits, hence resulting in the wrong values being computed.
> Since none of the calculations leave any room for fractional bits or
> seem to indicate any possible area of support, disallow such values
> altogether.  calculate_rc_params() in intel_vdsc.c performs an identical
> bitshift to get at this integer value.
>
> Fixes: b9080324d6ca ("drm/msm/dsi: add support for dsc data")
> Signed-off-by: Marijn Suijten <marijn.suijten@xxxxxxxxxxxxxx>

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>

> ---
>   drivers/gpu/drm/msm/dsi/dsi_host.c | 19 ++++++++++++++-----
>   1 file changed, 14 insertions(+), 5 deletions(-)

--
With best wishes
Dmitry