On 2020-11-26 3:11 p.m., Kazlauskas, Nicholas wrote:
> On 2020-11-26 2:50 p.m., Aurabindo Pillai wrote:
>> [Why&How]
>>
>> Set dpms off on the MST connector that was unplugged, for the side
>> effect of
>> releasing some references held through deallocation of mst payload.
>>
>> Signed-off-by: Aurabindo Pillai <aurabindo.pillai@xxxxxxx>
>> Signed-off-by: Eryk Brol <eryk.brol@xxxxxxx>
>> ---
>> .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 63 ++++++++++++++++++-
>> 1 file changed, 62 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
>> b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
>> index e213246e3f04..fc984cf6e316 100644
>> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
>> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
>> @@ -1984,6 +1984,64 @@ static void dm_gpureset_commit_state(struct
>> dc_state *dc_state,
>> return;
>> }
>> +static void dm_set_dpms_off(struct dc_link *link)
>> +{
>> + struct {
>> + struct dc_surface_update surface_updates[MAX_SURFACES];
>> + struct dc_stream_update stream_update;
>> + } * bundle;
>> + struct dc_stream_state *stream_state;
>> + struct dc_context *dc_ctx = link->ctx;
>> + int i;
>> +
>> + bundle = kzalloc(sizeof(*bundle), GFP_KERNEL);
>> +
>> + if (!bundle) {
>> + dm_error("Failed to allocate update bundle\n");
>> + return;
>> + }
>> +
>> + bundle->stream_update.dpms_off = kzalloc(sizeof(bool), GFP_KERNEL);
>
> You don't need to allocate memory for the bool. You can just use a local
> here, DC doesn't need it after the call ends.
>
> I think the same should apply to the surface updates as well. I'm not
> entirely sure how much stack the bundle takes up for a single stream
> here but it should be small enough that we can leave it on the stack.
>
>> +
>> + if (!bundle->stream_update.dpms_off) {
>> + dm_error("Failed to allocate update bundle\n");
>> + goto cleanup;
>> + }
>> +
>> + *bundle->stream_update.dpms_off = true;
>> +
>> + for (i = 0; i< MAX_PIPES; i++) {
>> + if (dc_ctx->dc->current_state->streams[i] == NULL)
>> + continue;
>> +
>> + if (dc_ctx->dc->current_state->streams[i]->link == link) {
>> + stream_state = dc_ctx->dc->current_state->streams[i];
>> + goto link_found;
>> + }
>> + }
>
> We shouldn't be reading from dc->current_state directly in DM, it's
> essentially private state.
>
> I think we should actually have a new helper here in dc_stream.h that's
> like:
>
> struct dc_stream_state *dc_stream_find_from_link(const struct dc_link
> *link);
>
> to replace this block of code.
>
> Note that any time we touch current_state we also need to be locking -
> it looks like this function is missing the appropriate calls to:
>
> mutex_lock(&adev->dm.dc_lock);
> mutex_unlock(&adev->dm.dc_lock);
>
> Regards,
> Nicholas Kazlauskas
>
>
Thank you for the review. Sent a v2
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