[argyllcms] Re: dispread fails with ubuntu packed argyllcms with i1pro
- From: Graeme Gill <graeme@xxxxxxxxxxxxx>
- To: argyllcms@xxxxxxxxxxxxx
- Date: Sun, 10 Jan 2010 08:58:00 +1100
Lars Tore Gustavsen wrote:
When I run dispread it stop the measurements at about patch 340 and
just hangs there. When I use the binary provided from Gill there is
no such error.
If you edit the source and change the SW_THREAD_TIMEOUT
#define to a smaller value (say 20.0 seconds), does it fail sooner ?
If so it's a concurrent access issue with the USB driver.
The way the switch is detected is that there is a concurrent
outstanding USB read that gets returned if the switch is hit. There
is normally a timeout of 10 minutes on this, so you get through
about 300 x 2 second display reads before it times out and the
timeout clashes with another USB read.
The switch read is actually necessary on the Rev A and Rev B
instruments, or the instrument suffers 1.5 second internal delays.
[The Rev D. may not be so sensitive since it uses a different
micro and seems to have more buffering its USB.]
libusb has to be able to deal with two threads accessing the
same device having independent timeouts. The original libusb V0.1
code didn't handle that.
[This is exactly why Argyll comes with its own copy of
libusb, and why I strongly object to Linux distributions
removing it - it's not a whim, there are very concrete reasons
for not trusting whatever version of libusb happens to be on
the system ! You certainly aren't doing yourselves or end users
any favors distributing broken versions of Argyll, and
I'm particularly unhappy about how it then reflects back
on upstream.]
Graeme Gill.
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