Re: [PATCH V2] Input: synaptics-rmi4 - filter incomplete relative packet.

[Dmitry Torokhov]

Hi Marge,

On Fri, Aug 12, 2022 at 04:43:25PM +0800, margeyang wrote:
> From: Marge Yang <marge.yang@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx>
> 
> RMI4 F03 supports the Stick function,
> it's designed to support relative packet.
> This patch supports the following case.
> When relative packet can't be reported completely,
> it may miss one byte or two byte.
> New Synaptics firmware will report PARITY error.
> When timeout error or parity error happens,
> RMI4 driver will sends 0xFE command and
> ask FW to Re-send stick packet again.

My understanding is that F03 is intended to be a pass-through mechanism
for PS/2-compatible devices. In that spirit all protocol handling and
validation should happen in psmouse driver that attaches to a serio port
provided by F03.

Historically we did not pay attention to parity and frame errors for
PS/2 mice/touchpads (and for keyboards on x86) but we coudl add such
code there. Do we actually observe this with RMI devices? Can RMI
firmware handle this better instead?

Thanks.

-- 
Dmitry