[PATCH] drm/amd/display: re-enable wait in pipelock, but add timeout

[Alex Deucher]

Ping?

On Fri, Nov 15, 2019 at 11:01 AM Alex Deucher <alexdeucher at gmail.com> wrote:
>
> Removing this causes hangs in some games, so re-add it, but add
> a timeout so we don't hang while switching flip types.
>
> Bug: https://bugzilla.kernel.org/show_bug.cgi?id=205169
> Bug: https://bugs.freedesktop.org/show_bug.cgi?id=112266
> Bug: https://bugzilla.kernel.org/show_bug.cgi?id=205169
> Signed-off-by: Alex Deucher <alexander.deucher at amd.com>
> ---
>  .../drm/amd/display/dc/dcn20/dcn20_hwseq.c    | 19 +++++++++++++++++++
>  1 file changed, 19 insertions(+)
>
> diff --git a/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_hwseq.c b/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_hwseq.c
> index 0046a099c9e9..120e62c5193c 100644
> --- a/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_hwseq.c
> +++ b/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_hwseq.c
> @@ -1033,6 +1033,25 @@ void dcn20_pipe_control_lock(
>         if (pipe->plane_state != NULL)
>                 flip_immediate = pipe->plane_state->flip_immediate;
>
> +       if (flip_immediate && lock) {
> +               const int TIMEOUT_FOR_FLIP_PENDING = 100000;
> +               int i;
> +
> +               for (i = 0; i < TIMEOUT_FOR_FLIP_PENDING; ++i) {
> +                       if (!pipe->plane_res.hubp->funcs->hubp_is_flip_pending(pipe->plane_res.hubp))
> +                               break;
> +                       udelay(1);
> +               }
> +
> +               if (pipe->bottom_pipe != NULL) {
> +                       for (i = 0; i < TIMEOUT_FOR_FLIP_PENDING; ++i) {
> +                               if (!pipe->bottom_pipe->plane_res.hubp->funcs->hubp_is_flip_pending(pipe->bottom_pipe->plane_res.hubp))
> +                                       break;
> +                               udelay(1);
> +                       }
> +               }
> +       }
> +
>         /* In flip immediate and pipe splitting case, we need to use GSL
>          * for synchronization. Only do setup on locking and on flip type change.
>          */
> --
> 2.23.0
>