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

[Harry Wentland]

On 2024-08-28 09:58, Alex Deucher wrote:
> 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>
> 

Acked-by: Harry Wentland <harry.wentland at amd.com>

Harry

>>
>> 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