A backend has to be able to handle all possible buffer sizes for then sane_read command. the command "scanimage -T" does test the behaviour of a backend with different buffer sizes.
xsane uses a sane_read with a buffer size of 64kB. Best regards Oliver Am Donnerstag, 18. Januar 2007 00:57 schrieb Thomas H. George: > Xsane color scans from my Epson Perfection 2400 scanner with a usb > connection fail after one or two scans. The scanner suddenly stalls in > mid-scan. The backend maintainer advised: > > " > It's very unlikely that a change in the backend caused that problem. The > scanner would probably not even start if something got broken. The EPSON > ESC/I protocol (which is used by your scanner) does not allow to control > the scan head in such a way, it either scans the complete selected area, > or it does not scan at all. > > One way to find out if something in the software changed is to go back > to an older version of the Sane system. > You could also try to get a log file by setting the SANE_DEBUG_EPSON > environment variable to 255. > > There is however one other possibility: If the USB system stalls, the > scanner can not get rid of it's data, and it can therefore not collect > any more data, and it may look like the scanner stalls. Does this happen > regardless of the scan resolution? > " > > The problem does seem to be that the usb system stalls, perhaps because > a buffer is full? scanimage has an option -B to change a buffer size. > Is there a buffer setting for xsane? If so, how is it set? > > Tom
