Re: [PATCH v3 0/5] Add SW_TABLET_MODE support for AMD SFH convertibles

[Basavaraj Natikar <bnatikar@amd.com>]

On 8/14/2026 6:14 PM, Jiri Kosina wrote:
> On Mon, 3 Aug 2026, Basavaraj Natikar wrote:
>
>> Add SW_TABLET_MODE support for AMD convertibles whose operating mode
>> (laptop or tablet) is reported by the Sensor Fusion Hub.
>>
>> Patches 1 and 2 are preparation: the first tracks the MP2 version
>> explicitly and the second serializes access to the shared emp2 pointer.
>> The third adds a way to read the operating mode. The fourth registers an
>> auxiliary device when the sensor is present, and the fifth is a small
>> input driver that binds to it and reports the posture to userspace.
>> Keeping the input handling in its own driver avoids pulling input/evdev
>> into the sensor transport driver.
>>
>> Changes in v3:
>> - Destroy the tablet-mode auxiliary device before the hardware teardown
>>    in .remove(), instead of from a devres action that runs afterwards,
>>    closing a use-after-teardown window (Sashiko review).
>> - Move the Makefile entry to its correct alphabetical position
>>    (Dmitry Torokhov).
>>
>> Changes in v2 (address the Sashiko review of v1):
>> - Read the operating-mode register only on confirmed MP2 v2, by tracking
>>    the MP2 version explicitly. On v1.0 that register overlaps the 64-bit
>>    DMA address programmed through C2P, so the earlier unconditional read
>>    could return DMA bits instead of the operating mode.
>> - Serialize the shared emp2 pointer and all exported readers under a
>>    mutex, so a concurrent unbind can no longer free the device while a
>>    reader is still dereferencing it.
>> - Publish emp2 only after initialization has populated the client data,
>>    and clear it early on the MP2 v2 remove path instead of from a
>>    prematurely registered devres action; this removes both the
>>    publish-before-init data race and the unconditional global clear on a
>>    probe failure.
>> - Destroy the tablet-mode auxiliary device and release its id on removal,
>>    and allocate the id dynamically so multiple instances cannot collide.
>> - Report the initial tablet-mode state before registering the input
>>    device, so userspace never observes a stale default posture.
>> - Rename the error variable from 'rc' to 'error' to follow the
>>    input-subsystem convention.
>>
>> v2: https://lore.kernel.org/all/20260803145801.3801862-1-Basavaraj.Natikar@amd.com/
>> v1: https://lore.kernel.org/all/20260721174422.3109166-1-Basavaraj.Natikar@amd.com/
> Now queued in hid.git#for-7.3/amd-sfh, sorry for the delay. Myself and
> Benjamin have been on a few weeks on leave in parallel, and then didn't
> really help with the throughput ... still recovering :)

Thanks a lot, Jiri, and no worries at all about the delay.
I really appreciate you and Benjamin taking the time to
review it. Hope you're both back to full strength soon.

Thanks again for queuing it up.

Thanks,
-- 
Basavaraj

>