linux-kernel - Re: [PATCH 1/1] media: dvb-usb/af9015, fix disconnection crashes

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Message-ID: <4B6AA211.1060707@gmail.com>
Date:	Thu, 04 Feb 2010 11:31:45 +0100
From:	Jiri Slaby <jirislaby@...il.com>
To:	Jiri Kosina <jkosina@...e.cz>
CC:	Antti Palosaari <crope@....fi>, mchehab@...radead.org,
	linux-kernel@...r.kernel.org,
	Mauro Carvalho Chehab <mchehab@...hat.com>,
	linux-media@...r.kernel.org, Pekka Sarnila <sarnila@...t.fi>,
	linux-input@...r.kernel.org
Subject: Re: [PATCH 1/1] media: dvb-usb/af9015, fix disconnection crashes

On 01/26/2010 02:08 PM, Jiri Kosina wrote:
>> In my understanding the cause of the remote problem is chipset bug which sets
>> USB2.0 polling interval to 4096ms. Therefore HID remote does not work at all
>> or starts repeating. It is possible to implement remote as polling from the
>> driver which works very well. But HID problem still remains. I have some hacks
>> in my mind to test to kill HID. One is to configure HID wrongly to see if it
>> stops outputting characters. Other way is try to read remote codes directly
>> from the chip memory.
> 
> Yes, Pekka Sarnila has added this workaround to the HID driver, as the 
> device is apparently broken.
> 
> I want to better understand why others are not hitting this with the 
> DVB remote driver before removing the quirk from HID code completely.

I think, we should go for a better way. Thanks Pekka for hints, I ended
up with the patch in the attachment. Could you try it whether it works
for you?

I have 2 dvb-t receivers and both of them need fullspeed quirk. Further
disable_rc_polling (a dvb_usb module parameter) must be set to not get
doubled characters now. And then, it works like a charm.

Note that, it's just some kind of proof of concept. A migration of
af9015 devices from dvb-usb-remote needs to be done first.

Ideas, comments?

regards,
-- 
js

View attachment "dvb-remote-fix.patch" of type "text/x-patch" (6005 bytes)