Re: [PATCH RESEND v5 0/7] Input: synaptics-rmi4 - add quirks for third party touchscreen controllers

[David Heidelberg <david@ixit.cz>]

On 07/08/2025 06:29, Dmitry Torokhov wrote:
> Hi David,
> 
> On Thu, Jul 31, 2025 at 11:06:50PM +0200, David Heidelberg via B4 Relay wrote:
>> With the growing popularity of running upstream Linux on mobile devices,
>> we're beginning to run into more and more edgecases. The OnePlus 6 is a
>> fairly well supported 2018 era smartphone, selling over a million units
>> in it's first 22 days. With this level of popularity, it's almost
>> inevitable that we get third party replacement displays, and as a
>> result, replacement touchscreen controllers.
>>
>> The OnePlus 6 shipped with an extremely usecase specific touchscreen
>> driver, it implemented only the bare minimum parts of the highly generic
>> rmi4 protocol, instead hardcoding most of the register addresses.
>>
>> As a result, the third party touchscreen controllers that are often
>> found in replacement screens, implement only the registers that the
>> downstream driver reads from. They additionally have other restrictions
>> such as heavy penalties on unaligned reads.
>>
>> This series attempts to implement the necessary workaround to support
>> some of these chips with the rmi4 driver. Although it's worth noting
>> that at the time of writing there are other unofficial controllers in
>> the wild that don't work even with these patches.
>>
>> We have been shipping these patches in postmarketOS for the last several
>> years, and they are known to not cause any regressions on the OnePlus
>> 6/6T (with the official Synaptics controller), however I don't own any
>> other rmi4 hardware to further validate this.
> 
> Sorry for not handling the patches in the last few submissions. I am
> planning on addressing them once merge window opens.

Hello Dmitry, kind reminder about the patch series as the window is open.

If you'll find a time, there is also one small, but important patchset 
improving the Linux phones/tablets experience here:

https://patchwork.kernel.org/project/linux-input/list/?series=987495&state=*&archive=both

David

> 
> Thanks.
> 

-- 
David Heidelberg