[sane-devel] Problem with libusb and 64 bits 2.6.25 kernel

[m. allan noah]

On Tue, May 27, 2008 at 4:01 PM, Nicolas <nicolas.martin at freesurf.fr> wrote:
>
> Le mardi 27 mai 2008 à 15:42 -0400, m. allan noah a écrit :
>> On Tue, May 27, 2008 at 3:29 PM, Nicolas <nicolas.martin at freesurf.fr> wrote:
>> > Le lundi 26 mai 2008 à 19:12 -0400, m. allan noah a écrit :
>> >> two random thoughts-
>> >>
>> >> 1. can he try 32 bit kernel on same exact machine, just to rule out
>> >> hardware problems?
>> >
>> > Good point, and to try other USB ports on the same machine, that needs
>> > to be confirmed first as it could be a HW issue
>> >
>> >> 2. is there a pattern to the timeouts, like always same number of
>> >> errors before a good packet?
>> >
>> > It looks to be a repetitive pattern, i.e. error occurs on a second
>> > "read" sequence when reading image data, but occurs also sometimes with
>> > smaller transaction control messages (write message, then read response
>> > immediately).
>> > I've asked to give a try with a small tempo between two successive image
>> > data readings, but do not have feedback yet.
>> >
>> > Thanks
>> >
>>
>> yes- it could be that his machine is too fast for the scanner, not
>> that it is 64 bits.
>>
>> allan
>
> But this would mean that with machines getting faster and faster,
> something needs to be adjusted, so that consecutive usb commands do not
> occur within a too short delay.
>
> Unfortunately, I did not see any spec for such timings in libusb.
> Maybe something about that is the usb spec ? need to check this point...
>
> Nicolas
>

there is no way to control this in libusb AFAIK, instead, you would
have to determine a dynamic delay period to add before all commands.

allan
-- 
"The truth is an offense, but not a sin"