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>
> ---
> .../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
>
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
