On Wed, 20 Aug 2025, Jouni Högander <jouni.hogan...@intel.com> wrote:
> Currently we are ignoriong drm_dp_dpcd_read return values when reading PSR
> and Panel Replay capability DPCD register. Rework intel_psr_dpcd a bit to
> take care of checking the return value.
Please switch to drm_dp_dpcd_read_data() while at it to be able to just
check for ret < 0.
BR,
Jani.
>
> Signed-off-by: Jouni Högander <jouni.hogan...@intel.com>
> ---
> drivers/gpu/drm/i915/display/intel_psr.c | 32 ++++++++++++++++--------
> 1 file changed, 21 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_psr.c
> b/drivers/gpu/drm/i915/display/intel_psr.c
> index 609df53f1ef1..68eb02127f47 100644
> --- a/drivers/gpu/drm/i915/display/intel_psr.c
> +++ b/drivers/gpu/drm/i915/display/intel_psr.c
> @@ -580,6 +580,16 @@ static void intel_dp_get_su_granularity(struct intel_dp
> *intel_dp)
> static void _panel_replay_init_dpcd(struct intel_dp *intel_dp)
> {
> struct intel_display *display = to_intel_display(intel_dp);
> + int ret;
> +
> + ret = drm_dp_dpcd_read(&intel_dp->aux, DP_PANEL_REPLAY_CAP_SUPPORT,
> + &intel_dp->pr_dpcd, sizeof(intel_dp->pr_dpcd));
> + if (ret != sizeof(intel_dp->pr_dpcd))
> + return;
> +
> + if
> (!(intel_dp->pr_dpcd[INTEL_PR_DPCD_INDEX(DP_PANEL_REPLAY_CAP_SUPPORT)] &
> + DP_PANEL_REPLAY_SUPPORT))
> + return;
>
> if (intel_dp_is_edp(intel_dp)) {
> if (!intel_alpm_aux_less_wake_supported(intel_dp)) {
> @@ -611,6 +621,15 @@ static void _panel_replay_init_dpcd(struct intel_dp
> *intel_dp)
> static void _psr_init_dpcd(struct intel_dp *intel_dp)
> {
> struct intel_display *display = to_intel_display(intel_dp);
> + int ret;
> +
> + ret = drm_dp_dpcd_read(&intel_dp->aux, DP_PSR_SUPPORT,
> intel_dp->psr_dpcd,
> + sizeof(intel_dp->psr_dpcd));
> + if (ret != sizeof(intel_dp->psr_dpcd))
> + return;
> +
> + if (!intel_dp->psr_dpcd[0])
> + return;
>
> drm_dbg_kms(display->drm, "eDP panel supports PSR version %x\n",
> intel_dp->psr_dpcd[0]);
> @@ -656,18 +675,9 @@ static void _psr_init_dpcd(struct intel_dp *intel_dp)
>
> void intel_psr_init_dpcd(struct intel_dp *intel_dp)
> {
> - drm_dp_dpcd_read(&intel_dp->aux, DP_PSR_SUPPORT, intel_dp->psr_dpcd,
> - sizeof(intel_dp->psr_dpcd));
> -
> - drm_dp_dpcd_read(&intel_dp->aux, DP_PANEL_REPLAY_CAP_SUPPORT,
> - &intel_dp->pr_dpcd, sizeof(intel_dp->pr_dpcd));
> -
> - if (intel_dp->pr_dpcd[INTEL_PR_DPCD_INDEX(DP_PANEL_REPLAY_CAP_SUPPORT)]
> &
> - DP_PANEL_REPLAY_SUPPORT)
> - _panel_replay_init_dpcd(intel_dp);
> + _psr_init_dpcd(intel_dp);
>
> - if (intel_dp->psr_dpcd[0])
> - _psr_init_dpcd(intel_dp);
> + _panel_replay_init_dpcd(intel_dp);
>
> if (intel_dp->psr.sink_psr2_support ||
> intel_dp->psr.sink_panel_replay_su_support)
--
Jani Nikula, Intel
