[RESEND 3/3] drm/amd/display: switch to guid_gen() to generate valid GUIDs

[Alex Deucher]

On Wed, Aug 28, 2024 at 9:53 AM Jani Nikula <jani.nikula at intel.com> wrote:
>
> On Wed, 28 Aug 2024, Daniel Vetter <daniel.vetter at ffwll.ch> 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 at intel.com>
> >>
> >> ---
> >>
> >> 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 at ffwll.ch>
>
> Thanks!
>
> Cc: AMD folks, ack for merging the series via drm-misc-next?

Unless Harry has any objections,
Acked-by: Alex Deucher <alexander.deucher at amd.com>

>
> 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