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

[Hamza Mahfooz <hamza.mahfooz@amd.com>]

On 8/28/24 10:06, Jani Nikula wrote:
> On Wed, 28 Aug 2024, Hamza Mahfooz <hamza.mahfooz@amd.com> 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@intel.com>
>>>
>>> ---
>>
>> Acked-by: Hamza Mahfooz <hamza.mahfooz@amd.com>
>>
>> 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