Re: Losing events from USB barcode reader

On Fri, Jun 03, 2011 at 10:15:11AM +0200, Thomas Petazzoni wrote:

Hello,

On Wed, 25 May 2011 17:38:32 +0200
Thomas Petazzoni [off-list ref] wrote:

quoted

Agreed. However, I don't know on which criteria should the kernel
decide what the size of the internal buffer should be, in this
particular case.

Any idea on how to adjust the kernel internal events buffer size for
this particular device ?

Since v2.6.36, the device may hint the size of the buffer through
input_set_events_per_packet. Perhaps, you could use a QUIRCK or
something like that to indicate that you need a larger buffer and then
use that to set the buffer to a size like 60, which is what is used by
most other uses of this indication. To compare to the minimum default
value, this is 8 input_event's in evdev per event. That is, a hint of 60
will allocate a buffer of 480 entries, instead of 64.

Regards,
Cascardo.

Thanks!

Thomas
-- 
Thomas Petazzoni, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com