ACK: [PATCH 0/4][SRU][U/L/K] Fix Monitor lost after replug WD19TBS to SUT port with VGA/DVI to type-C dongle Edit

[Tim Gardner]

On 5/31/23 7:51 PM, Koba Ko wrote:
> BugLink: https://bugs.launchpad.net/bugs/2021949
> 
> [Impact]
> Enabling CL1 (Controller Low Power) states during discovery of existing tunnels established by the system firmware can interfere with the operation of those tunnels.
> The DisplayPort tunnel establishment timeout of 1.5 seconds can be insufficient for some docking stations, leading to blank displays.
> 
> [Fix]
> CL1 states are now not enabled during discovery of existing tunnels. The TMU settings also remain unchanged.
> The timeout is increased to 3 seconds to allow more time for the DisplayPort connection manager handshake, fixing the issue of displays remaining blank.
> 
> [Test Cases]
> 1. plug docking station on the host
> 2. bring up the host and get into desktop.
> 3. flip docking station's cable.
> 4. check if the external monitor works well
> 
> [Where problems could occur]
> Low, If the handshake actually requires even more than 3 seconds in some cases, the timeout may still need to be increased further.
> 
> [Misc]
> Jammy needs more patches to enable the thunderbolt CLx and the SRU will be a huge,
> so skip Jammy.
> 
> 
> Mika Westerberg (3):
>    thunderbolt: Increase timeout of DP OUT adapter handshake
>    thunderbolt: Do not touch CL state configuration during discovery
>    thunderbolt: Increase DisplayPort Connection Manager handshake timeout
> 
>   drivers/thunderbolt/tb.c     | 17 ++++++++++++-----
>   drivers/thunderbolt/tunnel.c | 11 ++++++-----
>   2 files changed, 18 insertions(+), 10 deletions(-)
> 
Acked-by: Tim Gardner <tim.gardner at canonical.com>
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Tim Gardner
Canonical, Inc