Re: [PATCH 2/2] Documentation/arch/x86/amd-debugging: Add section about delay_suspend

[Daniel Gibson <daniel@gibson.sh>]

Hi,

On 24/06/2026 2:43 pm, Daniel Gibson wrote:
> Some Lenovo IdeaPad Slim 3 devices and similar with AMD CPUs (so far
> observed with Zen3 and Zen3+ CPUs) have a nonfunctional keyboard and
> lid switch after s2idle.
> 
> It helps to delay suspend by 2.5 seconds so the EC has some time
> to do whatever it needs to get done before suspend.
> 
> Devices known to be affected are matched automatically, others can
> enforce the delay with a amd_pmc module parameter.
> 
> This is now documented in amd-debugging.rst


any chance to get this merged?
As the delay_suspend parameter for the amd_pmc module are in all the 
current stable kernels >= 6.6 now (6.6.147, 6.12.100 etc) it would be 
great if the documentation was also available.

Cheers,
Daniel

> 
> Signed-off-by: Daniel Gibson <daniel@gibson.sh>
> ---
>   Documentation/arch/x86/amd-debugging.rst | 25 ++++++++++++++++++++++++
>   1 file changed, 25 insertions(+)
> 
> diff --git a/Documentation/arch/x86/amd-debugging.rst b/Documentation/arch/x86/amd-debugging.rst
> index 3176a1240fee..3725adb42673 100644
> --- a/Documentation/arch/x86/amd-debugging.rst
> +++ b/Documentation/arch/x86/amd-debugging.rst
> @@ -249,6 +249,31 @@ state entry.
>   
>   `commit 40b8c14936bd2 ("drm/amd/display: Disable unneeded hpd interrupts during dm_init") <https://git.kernel.org/torvalds/c/40b8c14936bd2>`_
>   
> +Keyboard and Lid Switch stop working after resume
> +-------------------------------------------------
> +On various variants of the Lenovo IdeaPad Slim 3 with Barcelo and Rembrandt CPUs
> +the lid switch and keyboard, or at least the Fn/Multimedia keys, stopped working
> +after resume, until the next reboot.
> +
> +This was caused by buggy firmware having timing probles, the EC needed some idle
> +time right before the CPU cores are suspended, or it got into an inconsistent state.
> +
> +For laptops that are known to be affected this workaround is enabled
> +automatically, to test this workaround on other machines you can set the
> +``delay_suspend`` parameter of the ``amd_pmc`` module.
> +
> +If you need to set the ``delay_suspend`` parameter to fix your machine, please
> +report this at platform-driver-x86@vger.kernel.org for it to be added to the
> +list of devices that need this workaround, so in future kernel versions it's
> +enabled automatically.
> +
> +Note that the current workaround isn't perfect: On some devices the problems still
> +happen if resume is triggered by a timer (wakealarm).
> +
> +`commit 9b9e60dd31da0 ("platform/x86/amd/pmc: Delay suspend for some Lenovo Laptops") <https://git.kernel.org/torvalds/c/9b9e60dd31da0>`_
> +
> +`commit 428b9fd2dce50 ("platform/x86/amd/pmc: Add delay_suspend module parameter") <https://git.kernel.org/torvalds/c/428b9fd2dce50>`_
> +
>   Runtime power consumption issues
>   ================================
>