Re: [PATCH RESEND] thunderbolt: Fix Thunderbolt 3 display flickering issue on 2nd hot plug onwards

[Sanjay R Mehta <sanmehta@amd.com>]

On 7/12/2023 10:12 PM, Greg KH wrote:
> On Wed, Jul 12, 2023 at 11:33:58AM +0530, Sanjay R Mehta wrote:
>>
>>
>> On 7/12/2023 11:23 AM, Greg KH wrote:
>>> On Wed, Jul 12, 2023 at 12:32:26AM -0500, Sanjay R Mehta wrote:
>>>> From: Sanjay R Mehta <sanju.mehta@amd.com>
>>>>
>>>> Previously, on unplug events, the TMU mode was disabled first
>>>> followed by the Time Synchronization Handshake, irrespective of
>>>> whether the tb_switch_tmu_rate_write() API was successful or not.
>>>>
>>>> However, this caused a problem with Thunderbolt 3 (TBT3)
>>>> devices, as the TSPacketInterval bits were always enabled by default,
>>>> leading the host router to assume that the device router's TMU was
>>>> already enabled and preventing it from initiating the Time
>>>> Synchronization Handshake. As a result, TBT3 monitors experienced
>>>> display flickering from the second hot plug onwards.
>>>>
>>>> To address this issue, we have modified the code to only disable the
>>>> Time Synchronization Handshake during TMU disable if the
>>>> tb_switch_tmu_rate_write() function is successful. This ensures that
>>>> the TBT3 devices function correctly and eliminates the display
>>>> flickering issue.
>>>>
>>>> Signed-off-by: Sanjay R Mehta <sanju.mehta@amd.com>
>>>> Signed-off-by: Sanath S <Sanath.S@amd.com>
>>>> ---
>>>>  drivers/thunderbolt/tmu.c | 4 +++-
>>>>  1 file changed, 3 insertions(+), 1 deletion(-)
>>>
>>> Why is this a RESEND?  What changed?
>>>
>>> And the ordering of the signed-off-by is incorrect.
>>>
>> Hi Greg, My Apologies, but am unable to comprehend what I should be
>> doing here. Please guide me on this.
> 
> Please go and take the AMD kernel developer class/training/something and
> work with internal developers to get this right before resending it
> again.
> 
Thanks. I'll get this right and send the patch.
> thanks,
> 
> greg k-h