On Wed, 28 Aug 2024, Daniel Vetter <daniel.vetter@xxxxxxxx> wrote:
> On Mon, Aug 12, 2024 at 03:23:12PM +0300, Jani Nikula wrote:
>> Instead of just smashing jiffies into a GUID, use guid_gen() to generate
>> RFC 4122 compliant GUIDs.
>>
>> Signed-off-by: Jani Nikula <jani.nikula@xxxxxxxxx>
>>
>> ---
>>
>> Side note, it baffles me why amdgpu has a copy of this instead of
>> plumbing it into drm mst code.
>
> Yeah ec5fa9fcdeca ("drm/amd/display: Adjust the MST resume flow") promised
> a follow-up, but that seems to have never materialized. Really should
> materialize though. Patch lgtm
>
> Reviewed-by: Daniel Vetter <daniel.vetter@xxxxxxxx>
Thanks!
Cc: AMD folks, ack for merging the series via drm-misc-next?
BR,
Jani.
>
>
>> ---
>> .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 23 ++++++++++---------
>> 1 file changed, 12 insertions(+), 11 deletions(-)
>>
>> 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 72c10fc2c890..ce05e7e2a383 100644
>> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
>> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
>> @@ -2568,9 +2568,9 @@ static int dm_late_init(void *handle)
>>
>> static void resume_mst_branch_status(struct drm_dp_mst_topology_mgr *mgr)
>> {
>> + u8 buf[UUID_SIZE];
>> + guid_t guid;
>> int ret;
>> - u8 guid[16];
>> - u64 tmp64;
>>
>> mutex_lock(&mgr->lock);
>> if (!mgr->mst_primary)
>> @@ -2591,26 +2591,27 @@ static void resume_mst_branch_status(struct drm_dp_mst_topology_mgr *mgr)
>> }
>>
>> /* Some hubs forget their guids after they resume */
>> - ret = drm_dp_dpcd_read(mgr->aux, DP_GUID, guid, 16);
>> - if (ret != 16) {
>> + ret = drm_dp_dpcd_read(mgr->aux, DP_GUID, buf, sizeof(buf));
>> + if (ret != sizeof(buf)) {
>> drm_dbg_kms(mgr->dev, "dpcd read failed - undocked during suspend?\n");
>> goto out_fail;
>> }
>>
>> - if (memchr_inv(guid, 0, 16) == NULL) {
>> - tmp64 = get_jiffies_64();
>> - memcpy(&guid[0], &tmp64, sizeof(u64));
>> - memcpy(&guid[8], &tmp64, sizeof(u64));
>> + import_guid(&guid, buf);
>>
>> - ret = drm_dp_dpcd_write(mgr->aux, DP_GUID, guid, 16);
>> + if (guid_is_null(&guid)) {
>> + guid_gen(&guid);
>> + export_guid(buf, &guid);
>>
>> - if (ret != 16) {
>> + ret = drm_dp_dpcd_write(mgr->aux, DP_GUID, buf, sizeof(buf));
>> +
>> + if (ret != sizeof(buf)) {
>> drm_dbg_kms(mgr->dev, "check mstb guid failed - undocked during suspend?\n");
>> goto out_fail;
>> }
>> }
>>
>> - import_guid(&mgr->mst_primary->guid, guid);
>> + guid_copy(&mgr->mst_primary->guid, &guid);
>>
>> out_fail:
>> mutex_unlock(&mgr->lock);
>> --
>> 2.39.2
>>
--
Jani Nikula, Intel
