Re: [PATCH] hwmon: (corsair-psu) serialize debugfs access against hwmon

[Guenter Roeck]

On Tue, Aug 04, 2026 at 04:11:11AM +0000, Wilken Gottwalt wrote:
> > 
> > Gemini tells me that fixing the raw event problem will require a spinlock to
> > protect the completion and a separate receive buffer. No idea if it is correct,
> > but other drivers do the same, so it may have a point. Either case, this is a
> > bit too much to do without hardware to test, and I'd rather prefer to leave this
> > up to Wilken.
> 
> I was working at that one, too, because I saw Claude Opus hinting on that one.
> But it drove me crazy, because every AI is saying something slighty different. I
> can not really pin down which one is actually the real solution. I tried to read
> through the subsystems code and other drivers, but, argh, I don't know. I was
> playing with the idea to (1) remove the raw HID mode completely or (2) make the
> driver switchable, raw HID or normal HID, but not both at the same time. On the
> other hand, in my Github repo where I develop the driver, I also have a tool
> which demonstrates how to access the PSU completely in userspace via libhidpi.
> There is actually no need to provide the raw HID access.
> 

Have a look at the patch below. It is part AI (Gemini) generated and part me.
Sashiko is happy with it, but of course that doesn't mean it is perfect or
even correct. It does look good to me, though.

Making Sashiko happy required all core elements of the patch:
- the spinlock
- the separate receive buffer
- the rcv_pending boolean
- the size check in corsairpsu_raw_event()

Sashiko reports race conditions if I drop just one of those elements.

Guenter

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