This is a note to let you know that I've just added the patch titled
thunderbolt: Fix Thunderbolt 3 display flickering issue on 2nd hot plug onwards
to the 6.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
thunderbolt-fix-thunderbolt-3-display-flickering-issue-on-2nd-hot-plug-onwards.patch
and it can be found in the queue-6.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 583893a66d731f5da010a3fa38a0460e05f0149b Mon Sep 17 00:00:00 2001
From: Sanjay R Mehta <sanju.mehta@xxxxxxx>
Date: Wed, 2 Aug 2023 06:11:49 -0500
Subject: thunderbolt: Fix Thunderbolt 3 display flickering issue on 2nd hot plug onwards
From: Sanjay R Mehta <sanju.mehta@xxxxxxx>
commit 583893a66d731f5da010a3fa38a0460e05f0149b upstream.
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.
Co-developed-by: Sanath S <Sanath.S@xxxxxxx>
Signed-off-by: Sanath S <Sanath.S@xxxxxxx>
Signed-off-by: Sanjay R Mehta <sanju.mehta@xxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
[ USB4v2 introduced support for uni-directional TMU mode as part of
d49b4f043d63 ("thunderbolt: Add support for enhanced uni-directional TMU mode")
This is not a stable candidate commit, so adjust the code for backport. ]
Signed-off-by: Mario Limonciello <mario.limonciello@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/thunderbolt/tmu.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--- a/drivers/thunderbolt/tmu.c
+++ b/drivers/thunderbolt/tmu.c
@@ -415,7 +415,8 @@ int tb_switch_tmu_disable(struct tb_swit
* uni-directional mode and we don't want to change it's TMU
* mode.
*/
- tb_switch_tmu_rate_write(sw, TB_SWITCH_TMU_RATE_OFF);
+ ret = tb_switch_tmu_rate_write(sw, TB_SWITCH_TMU_RATE_OFF);
+ return ret;
tb_port_tmu_time_sync_disable(up);
ret = tb_port_tmu_time_sync_disable(down);
Patches currently in stable-queue which might be from sanju.mehta@xxxxxxx are
queue-6.4/thunderbolt-fix-thunderbolt-3-display-flickering-issue-on-2nd-hot-plug-onwards.patch
