Reviewed-by: Lyude Paul <lyude@xxxxxxxxxx>
On Fri, 2020-04-17 at 18:27 +0300, Ville Syrjala wrote:
> From: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
>
> Make intel_dp_check_mst_status() somewhat legible by humans.
>
> Note that the return value of drm_dp_mst_hpd_irq() is always
> either 0 or -ENOMEM, and we never did anything with the latter
> so we can just ignore the whole thing.
>
> We can also get rid of the direct drm_dp_mst_topology_mgr_set_mst(false)
> call since returning -EINVAL causes the caller to do the very same call
> for us.
>
> Cc: Lyude Paul <lyude@xxxxxxxxxx>
> Signed-off-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
> ---
> drivers/gpu/drm/i915/display/intel_dp.c | 88 ++++++++++++-------------
> 1 file changed, 41 insertions(+), 47 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c
> b/drivers/gpu/drm/i915/display/intel_dp.c
> index 48397b2c08cf..4d4898db38e9 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> @@ -5628,61 +5628,55 @@ static int
> intel_dp_check_mst_status(struct intel_dp *intel_dp)
> {
> struct drm_i915_private *i915 = dp_to_i915(intel_dp);
> - bool bret;
>
> - if (intel_dp->is_mst) {
> - u8 esi[DP_DPRX_ESI_LEN] = { 0 };
> - int ret = 0;
> + if (!intel_dp->is_mst)
> + return -EINVAL;
> +
> + WARN_ON_ONCE(intel_dp->active_mst_links < 0);
> +
> + for (;;) {
> + u8 esi[DP_DPRX_ESI_LEN] = {};
> + bool bret, handled;
> int retry;
> - bool handled;
>
> - WARN_ON_ONCE(intel_dp->active_mst_links < 0);
> bret = intel_dp_get_sink_irq_esi(intel_dp, esi);
> -go_again:
> - if (bret == true) {
> -
> - /* check link status - esi[10] = 0x200c */
> - if (intel_dp->active_mst_links > 0 &&
> - !drm_dp_channel_eq_ok(&esi[10], intel_dp-
> >lane_count)) {
> - drm_dbg_kms(&i915->drm,
> - "channel EQ not ok,
> retraining\n");
> - intel_dp_start_link_train(intel_dp);
> - intel_dp_stop_link_train(intel_dp);
> - }
> -
> - drm_dbg_kms(&i915->drm, "got esi %3ph\n", esi);
> - ret = drm_dp_mst_hpd_irq(&intel_dp->mst_mgr, esi,
> &handled);
> -
> - if (handled) {
> - for (retry = 0; retry < 3; retry++) {
> - int wret;
> - wret = drm_dp_dpcd_write(&intel_dp-
> >aux,
> - DP_SINK_COUNT
> _ESI+1,
> - &esi[1], 3);
> - if (wret == 3) {
> - break;
> - }
> - }
> -
> - bret = intel_dp_get_sink_irq_esi(intel_dp,
> esi);
> - if (bret == true) {
> - drm_dbg_kms(&i915->drm,
> - "got esi2 %3ph\n", esi);
> - goto go_again;
> - }
> - } else
> - ret = 0;
> -
> - return ret;
> - } else {
> + if (!bret) {
> drm_dbg_kms(&i915->drm,
> "failed to get ESI - device may have
> failed\n");
> - intel_dp->is_mst = false;
> - drm_dp_mst_topology_mgr_set_mst(&intel_dp->mst_mgr,
> - intel_dp->is_mst);
> + return -EINVAL;
> + }
> +
> + /* check link status - esi[10] = 0x200c */
> + /*
> + * FIXME kill this and use the SST retraining approach
> + * for MST as well.
> + */
> + if (intel_dp->active_mst_links > 0 &&
> + !drm_dp_channel_eq_ok(&esi[10], intel_dp->lane_count)) {
> + drm_dbg_kms(&i915->drm,
> + "channel EQ not ok, retraining\n");
> + intel_dp_start_link_train(intel_dp);
> + intel_dp_stop_link_train(intel_dp);
> + }
> +
> + drm_dbg_kms(&i915->drm, "got esi %3ph\n", esi);
> +
> + drm_dp_mst_hpd_irq(&intel_dp->mst_mgr, esi, &handled);
> + if (!handled)
> + break;
> +
> + for (retry = 0; retry < 3; retry++) {
> + int wret;
> +
> + wret = drm_dp_dpcd_write(&intel_dp->aux,
> + DP_SINK_COUNT_ESI+1,
> + &esi[1], 3);
> + if (wret == 3)
> + break;
> }
> }
> - return -EINVAL;
> +
> + return 0;
> }
>
> static bool
> --
> 2.24.1
>
--
Cheers,
Lyude Paul (she/her)
Associate Software Engineer at Red Hat
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