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From: Oliver Neukum <oneukum@suse.com>
To: Lauri Jakku <lja@iki.fi>, benjamin.tissoires@redhat.com
Cc: jikos@kernel.org, linux-input@vger.kernel.org,
	gregkh@linuxfoundation.org, linux-usb@vger.kernel.org
Subject: Re: [PATCH v5] USB: HID: random timeout failures tackle try.
Date: Wed, 05 Feb 2020 11:03:25 +0100	[thread overview]
Message-ID: <1580897005.9756.3.camel@suse.com> (raw)
In-Reply-To: <20200204175238.3817-1-lja@iki.fi>

Am Dienstag, den 04.02.2020, 19:52 +0200 schrieb Lauri Jakku:
> -- v1 ------------------------------------------------------------
> send, 20ms apart, control messages, if error is timeout.
> 
> There is multiple reports of random behaviour of USB HID devices.
> 
> I have mouse that acts sometimes quite randomly, I debugged with
> logs others have published that there is HW timeouts that leave
> device in state that it is errorneus.
> 
> To fix this I introduced retry mechanism in root of USB HID drivers.
> 
> Fix does not slow down operations at all if there is no -ETIMEDOUT
> got from control message sending. If there is one, then sleep 20ms
> and try again. Retry count is 20 witch translates maximium of 400ms
> before giving up.
> 
> NOTE: This does not sleep anymore then before, if all is golden.

This is well if retries help. In case any other form of error handling,
such as a reset, are needed, these retries will hamper recovery.
It seems to me that you really should use a separate function
for this.

	Regards
		Oliver


      parent reply	other threads:[~2020-02-05 10:03 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-04 17:52 [PATCH v5] USB: HID: random timeout failures tackle try Lauri Jakku
2020-02-04 18:07 ` Alan Stern
2020-02-04 20:14   ` Lauri Jakku
2020-02-04 18:11 ` Greg KH
2020-02-04 18:15 ` Greg KH
2020-02-04 20:05   ` Lauri Jakku
2020-02-05 10:03 ` Oliver Neukum [this message]

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