Re: [PATCH] thunderbolt: Improve redrive mode handling

[Mika Westerberg <mika.westerberg@linux.intel.com>]

On Wed, Dec 11, 2024 at 12:35:29PM +0200, Mika Westerberg wrote:
> When USB-C monitor is connected directly to Intel Barlow Ridge host, it
> goes into "redrive" mode that basically routes the DisplayPort signals
> directly from the GPU to the USB-C monitor without any tunneling needed.
> However, the host router must be powered on for this to work. Aaron
> reported that there are a couple of cases where this will not work with
> the current code:
> 
>   - Booting with USB-C monitor plugged in.
>   - Plugging in USB-C monitor when the host router is in sleep state
>     (runtime suspended).
>   - Plugging in USB-C device while the system is in system sleep state.
> 
> In all these cases once the host router is runtime suspended the picture
> on the connected USB-C display disappears too. This is certainly not
> what the user expected.
> 
> For this reason improve the redrive mode handling to keep the host
> router from runtime suspending when detect that any of the above cases
> is happening.
> 
> Fixes: a75e0684efe5 ("thunderbolt: Keep the domain powered when USB4 port is in redrive mode")
> Reported-by: Aaron Rainbolt <arainbolt@kfocus.org>
> Closes: https://lore.kernel.org/linux-usb/20241009220118.70bfedd0@kf-ir16/
> Cc: stable@vger.kernel.org
> Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>

Applied to thunderbolt.git/fixes.