Re: [PATCHv2] Input: xpad - Fix double URB submission races

From: Laura Abbott
Date: Tue Aug 25 2015 - 00:22:21 EST

On 08/21/2015 09:50 AM, Dmitry Torokhov wrote:
Hi Laura,

On Mon, Aug 10, 2015 at 05:26:12PM -0700, Laura Abbott wrote:
v2: Created a proper queue for events instead of just dropping them

How long does it take for the queue to exhaust your memory if you keep
bombarding the driver with requests?

My script which changes the LEDs as fast as possible ran for 7+ hours on
my machine with 16GB of RAM without exhausting all of it. This is also a
very extreme case as almost any kind of delay between sending
commands will drain the queue.
I do not think you need a queue. I believe the nature of LEDs and rumble
force feedback effect is such that you can discard all requests but the
latest that arrived between the moment you submitted a request to the
device and the moment you are ready submit a new one.

So your suggestion is to only keep a single item in the queue?


To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at