[opensuse-factory] sane-backends / hplip: enable more backends by default?
Hi, I was just wondering why xsane on Tumbleweed detected no devices although I had a HPLIP scanner configured. The reason is simply that all backends are commented out in /etc/sane.d/dll.conf by default. Together with sane-backends- autoconfig, that may work well with USB scanners, but not with network scanners like mine. It's also in stark contrast with Fedora, where only 16 out of 88 sane backends are commented out in the shipped dll.conf (xsane startup "scanning for devices" takes about 5s in that configuration on my laptop, compared to roughly 2s when only the hplip/hpaio backend is enabled). I understand that users are supposed to run "yast2 scanner" to enable their scanner HW. That works, but I wouldn't call it a smooth user experience for my network scanner (none of the many HP scanners the tool offered matched mine even remotely - I knew it was fine to choose just any "hpaio" device, but would every user have known that with confidence)? AFAICS, the completed "yast2 scanner" run had no effect other than uncommenting "hpaio" in dll.conf. Here comes the question: Couldn't we improve the openSUSE user experience by enabling more sane-backends by default? Regards, Martin PS: for HPLIP and other "external" backends, it would be cleaner to register the backend in /etc/sane.d/dll.d rather than in /etc/sane/dll.conf directly, but that would require YaST support as well. -- Dr. Martin Wilck <mwilck@suse.com>, Tel. +49 (0)911 74053 2107 SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton HRB 21284 (AG Nürnberg) -- To unsubscribe, e-mail: opensuse-factory+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse-factory+owner@opensuse.org
Hello, only FYI On Dec 7 10:31 Martin Wilck wrote (excerpt):
... all backends are commented out in /etc/sane.d/dll.conf by default
See sane-backends.changes that reads (excerpt): ------------------------------------------------------------------- Wed Sep 12 17:16:16 CEST 2001 - freitag@suse.de ... Disabled all dll-entries in /etc/sane.d/dll.conf to avoid probs with wrong device detection which happend in the past. The yast module enables the correct one, added a README.SuSE to the sane package doc path that describes this change. ------------------------------------------------------------------- Accordingly sane-backends.spec contains --------------------------------------------------------------------------- # Disable all backends in /etc/sane.d/dll.conf to avoid problems # when backends are active by default: perl -pi -e 's/^([^#].*)$/#$1/' %{buildroot}%{_sysconfdir}/sane.d/dll.conf --------------------------------------------------------------------------- I inherited it this way and I have zero knowledge what the actual reasoning behind was at that time. But I know there have been issues with conflicting different SANE backends for one same model. I think it could arbitrarily fail when two different SANE backends work for the same model and both backends try to communicate more or less simultaneously with the same device. This means at least one would have to ensure that it cannot happen that more than one backend is by default active for each of all the supported models. Kind Regards Johannes Meixner -- SUSE LINUX GmbH - GF: Felix Imendoerffer, Jane Smithard, Graham Norton - HRB 21284 (AG Nuernberg) -- To unsubscribe, e-mail: opensuse-factory+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse-factory+owner@opensuse.org
Hello, an addedum FYI: On Dec 7 15:02 Johannes Meixner wrote (excerpt):
On Dec 7 10:31 Martin Wilck wrote (excerpt):
... all backends are commented out in /etc/sane.d/dll.conf by default
See also "SANE Backends" at https://en.opensuse.org/SDB:Configuring_Scanners that reads (excerpt): ---------------------------------------------------------- If several backends are activated at the same time, there may be a conflict between the backends. If this is the case, try if it works if you only activate one backend at a time. ---------------------------------------------------------- I think I do correctly remember that I have had issues in the past in particular with Epson scanners where several backends are available that support them, free software backends in sane-backends and also the one from the non-free Epson (Avasys) Iscan software. Nowadays one could expect even more issues with possibly conflicting by default activated sane-backends backends versus proprietary backends from scanner manufacturers (e.g. from Brother and so on). On the other hand perhaps nowadays all "just works well" regardless how many programs communicate with one same USB scanner device - I don't know. Perhaps when everything just works well for other Linux distributors, we could "simply change" and do the same? The obvious prerequirement for such a change is someone at openSUSE who will deal with possibly incoming issues if we enable several backends by default. Kind Regards Johannes Meixner -- SUSE LINUX GmbH - GF: Felix Imendoerffer, Jane Smithard, Graham Norton - HRB 21284 (AG Nuernberg) -- To unsubscribe, e-mail: opensuse-factory+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse-factory+owner@opensuse.org
On Wed, 2016-12-07 at 15:24 +0100, Johannes Meixner wrote:
See also "SANE Backends" at https://en.opensuse.org/SDB:Configuring_Scanners that reads (excerpt): ---------------------------------------------------------- If several backends are activated at the same time, there may be a conflict between the backends. If this is the case, try if it works if you only activate one backend at a time. ----------------------------------------------------------
I think I do correctly remember that I have had issues in the past in particular with Epson scanners where several backends are available that support them, free software backends in sane-backends and also the one from the non-free Epson (Avasys) Iscan software.
Nowadays one could expect even more issues with possibly conflicting by default activated sane-backends backends versus proprietary backends from scanner manufacturers (e.g. from Brother and so on).
On the other hand perhaps nowadays all "just works well" regardless how many programs communicate with one same USB scanner device - I don't know.
Perhaps when everything just works well for other Linux distributors, we could "simply change" and do the same?
At least the bug queue for sane-backends for Fedora and Debian isn't extremely long. Of course every "my scanner doesn't work" bug report might be caused by conflicting backends.
The obvious prerequirement for such a change is someone at openSUSE who will deal with possibly incoming issues if we enable several backends by default.
We could create a branch and ask people for testing for regressions. Another question would be if, and how, "yast2 scanner" would be able to deal with a change like that. Best, Martin -- Dr. Martin Wilck <mwilck@suse.com>, Tel. +49 (0)911 74053 2107 SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton HRB 21284 (AG Nürnberg) -- To unsubscribe, e-mail: opensuse-factory+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse-factory+owner@opensuse.org
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Johannes Meixner -
Martin Wilck