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

[Hamza Mahfooz <hamza.mahfooz@xxxxxxx>]

On 8/28/24 10:06, Jani Nikula wrote:
> On Wed, 28 Aug 2024, Hamza Mahfooz <hamza.mahfooz@xxxxxxx> wrote:
> > On 8/12/24 08:23, 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>
> > >
> > > ---
> >
> > Acked-by: Hamza Mahfooz <hamza.mahfooz@xxxxxxx>
> >
> > I would prefer to take this series through the amdgpu tree though,
> > assuming nobody minds.
>
> How long is it going to take for that to get synced back to
> drm-misc-next though?

It might take awhile, so it's probably best to merge it through
drm-misc-next.

> BR,
> Jani.
>
>
> > > Side note, it baffles me why amdgpu has a copy of this instead of
> > > plumbing it into drm mst code.
> > > ---
> > >    .../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);
--
Hamza