[PATCH] drm/dp_mst: Correct the bug in drm_dp_update_payload_part1()

[Lyude Paul]

On Mon, 2019-12-02 at 11:58 +0800, Wayne Lin wrote:
> [Why]
> If the payload_state is DP_PAYLOAD_DELETE_LOCAL in series, current
> code doesn't delete the payload at current index and just move the
> index to next one after shuffling payloads.
> 
> [How]
> After shuffling payloads, decide whether to move on index or not
> according to payload_state of current payload.
> 
> Signed-off-by: Wayne Lin <Wayne.Lin at amd.com>
> ---
>  drivers/gpu/drm/drm_dp_mst_topology.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c
> b/drivers/gpu/drm/drm_dp_mst_topology.c
> index 81e92b260d7a..8da5d461ea01 100644
> --- a/drivers/gpu/drm/drm_dp_mst_topology.c
> +++ b/drivers/gpu/drm/drm_dp_mst_topology.c
> @@ -3176,7 +3176,8 @@ int drm_dp_update_payload_part1(struct
> drm_dp_mst_topology_mgr *mgr)
>  			drm_dp_mst_topology_put_port(port);
>  	}
>  
> -	for (i = 0; i < mgr->max_payloads; i++) {
> +	for (i = 0; i < mgr->max_payloads;
> +		(mgr->payloads[i].payload_state == DP_PAYLOAD_DELETE_LOCAL) ?
> i : i++) {

Took me a moment to figure out what this line was actually doing. Nice catch
by the way!

Anyway: let's just drop this line to avoid making things confusing to read,
drop i++ from the for loop instead, and just rewrite it so it looks like this:

for (i = 0; i < mgr->max_payloads; /* do nothing */) {
	if (mgr->payloads[i].payload_state != DP_PAYLOAD_DELETE_LOCAL) {
		i++;
		continue;
	}

With those changes, this patch is:

Reviewed-by: Lyude Paul <lyude at redhat.com>

I can go ahead and push these patches to drm-misc for you once you've sent me
the v2
>  		if (mgr->payloads[i].payload_state != DP_PAYLOAD_DELETE_LOCAL)
>  			continue;
>  
-- 
Cheers,
	Lyude Paul