linux-kernel - Re: [PATCH v2] staging: r8188eu: use a delayed worker for led updates

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Message-ID: <c4ea42f1-bacb-e7d2-1a97-ba8dd3853ffe@gmail.com>
Date:   Sat, 27 Nov 2021 08:42:08 +0100
From:   Michael Straube <straube.linux@...il.com>
To:     Martin Kaiser <martin@...ser.cx>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     Larry Finger <Larry.Finger@...inger.net>,
        Phillip Potter <phil@...lpotter.co.uk>,
        linux-staging@...ts.linux.dev, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] staging: r8188eu: use a delayed worker for led updates

On 11/26/21 12:41, Martin Kaiser wrote:
> The led layer uses a combination of timer and worker for periodic led
> updates, e.g. for blinking. The reason seems to be that blocking
> operations like a usb read are not allowed in a timer handler.
> 
> Replace the combination of timer and worker with a delayed worker.
> 
> Convert the timeout defines from milliseconds to jiffies to make them
> usable as delays for the delayed worker. Shorten the names of the defines
> and rename the work item to make checkpatch happy.
> 
> Other layers may call SwLedControlMode1 to update the led state. Such
> an update may result in cancelling the delayed worker. SwLedControlMode1
> might be called in interrupt context, we must use cancel_delayed_work to
> cancel the worker. cancel_delayed_work_sync waits until the worker is
> finished, this is not allowed in interrupt context.
> 
> DeInitLed871x is called when the driver is removed or when the system
> goes into standby. We may use cancel_delayed_work_sync here to cancel
> the delayed worker.
> 
> Signed-off-by: Martin Kaiser <martin@...ser.cx>
> ---
> v2:
>   - do not block if we cancel a delayed worker in interrupt context
> 

Hi Martin,

v2 works for me without any sleeping/scheduling while atomic bugs.

Thanks,
Michael