Can you try using scanimage -B ? allan
On Sat, Jun 27, 2015 at 2:07 PM, Yuval Levy <yuval.l...@ryerson.ca> wrote: > Good day developers! > > I need direction and help tracking down a bug. I have done some > testing, described in detail below, and found that on my system > scanimage hangs if the data for a single line is more than 16384 bytes. > > My intuition is that somewhere in the driver or in the scanning software > there is a 16384 bytes limit for a single line, possibly a buffer or a > counter, and the scanner times out when trying to scan a too wide > document at too high resolution. > > Hardware: > * Brother MFC-6490CW connected via the network (but I tested also with > USB connection and the same limit applies) > * A plain simple desktop PC, Intel i3-2125, 8GB RAM > * Also tested with an ultrabook, Intel i5-5400, 8GB RAM > > Operating System: > * Main operating system on both machines: Xubuntu 14.04.2 LTS 64-bit > * Tested with Ubuntu 15.04 32-bit as well (same results) > * Tested with Windows 7 (no problems at all) > > Reproducing the issue: > > SANE_DEBUG_DLL=128 scanimage -d "brother3:net1;dev0" --format=tiff -p > --mode "24bit Color" --resolution=600dpi --source="FlatBed" -l 0 -t 0 -x > 232 -y 10 > /tmp/test.tif > > Relevant output: > > [dll] sane_start(handle=0xcff680) > [dll] sane_get_parameters(handle=0xcff680,params=0x7ffc24ac06f0) > [dll] > sane_read(handle=0xcff680,data=0xcffc20,maxlen=32768,lenp=0x7ffc24ac06e4) > > then there is a long wait, the scanner times out (hear the noise of the > lamp going back into rest position), scanimage hangs for a while and > then goes wild until interrupted, printing a flurry of > > [dll] > sane_read(handle=0xcff680,data=0xcffc20,maxlen=32768,lenp=0x7ffc24ac06e4) > > Rounding up the issue: > * No problems scanning that size/density in Windows -- tells me it is > not an issue with the MFC-6940CW itself and narrows the search field to > the linux driver and/or scanning software > * The problem is the same whether I connect the scanner via network (my > default setup) or USB -- tells me it is not an issue with how the data > is transmitted > * The problem is the same in Xubuntu 14.04.2 64-bit and in Ubuntu 15.04 > 32-bit -- tells me it is not an issue of whether the software was > compiled for 32 or 64 bits, nor that there has been recent addition to > the 'buntu repository version of scanimage that solved the issue > > Limiting the issue: scanimage performs as expected if either of these > parameters is changed: > ** -x is smaller than 232 > ** --mode is "True Gray" > ** --resolution=600dpi > > All three changes have one thing in common: they reduce the weight of > the data generated when scanning one line. > > At -x 231, the resulting image is 5456 pixels wide, which is 16368 bytes > at a 24bit. Very close to 16384, a power of two number often used to > size buffers. My suspicion is that somewhere between the scanning > software and the driver there is a buffer or a counter limited to 16484 > bytes. When that limit is reached, the scanner is left hanging until it > times out. > > I am at the end of my own resources and need further direction / help. > While I do have some experience with building object code from source > code and can follow directions to modify little things and test them, I > am unfamiliar with SANE. Moreover, part of the software (Brother's > driver) is closed sourced, making it difficult to analyze. Can somebody > be kind, validate or deconstruct my analysis, and point me to the next > step in identifying and solving the bottleneck? Short of falling back > to Windows I do not know what to do, and I will rather run this high > volume low priority scan job in the background on my workstation than go > through the trouble of setting up an additional machine for the job. > > Many thanks in advance! > Yuv > > -- > Yuval Levy, JD, MBA, CFA > > > -- > sane-devel mailing list: sane-devel@lists.alioth.debian.org > http://lists.alioth.debian.org/cgi-bin/mailman/listinfo/sane-devel > Unsubscribe: Send mail with subject "unsubscribe your_password" > to sane-devel-requ...@lists.alioth.debian.org -- "well, I stand up next to a mountain- and I chop it down with the edge of my hand" -- sane-devel mailing list: sane-devel@lists.alioth.debian.org http://lists.alioth.debian.org/cgi-bin/mailman/listinfo/sane-devel Unsubscribe: Send mail with subject "unsubscribe your_password" to sane-devel-requ...@lists.alioth.debian.org
