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Kernel Maintainer Kills Philips USB Camera Support
outanowhere writes "The author of the Philips webcams kernel module has thrown in the towel and quit providing the pwc and pwcx kernel modules which make using Philips-based USB cameras such as those from Logitech and Philips possible with Linux.
According to the author, the last straw was when a kernel maintainer changed his pwc module to make using the binary-only pwcx compression module impossible.
It is a victory for obsessive kernel-purists but a major loss for all Linux users."
I met the maintainer once (although he lives relativly close), nice guy, but I kinda think this is just a useless move to annoy him, there are many fully binary only modules out there and he makes the effort to make opensource what he can (NDA) but provides a binary only module (on his own website) to add some more functionality (larger image/higher fps).
As a developer for a very small company, trying to get our Open Source driver into the 2.4 kernel was a nightmare.
For several reasons, user land was not a viable option. The elitist control freak running the show wouldn't let our code in. Consequently, we lost some good free advertising, and possibly some customers in order to feed the ego of some guy bent on denying anything he thought could go through user land instead.
We ended up just putting the source on our web site. Several customers already use it very successfully. But none the less, we were blocked from contributing while trying to uphold the spirit and ideals of OSS. I can only imagine how much the poor sap from Philips was being jerked around.
That being said, Linux was a stroll through a grassy meadow compared to trying to go through WHQL testing for M$.
Quando Omni Flunkus Moritati
One ironic twist is that LavaRnd used only the PWC (open source) module. We did NOT use the PWCX (binary-only) module. Our hotplug script did an rmmod of the pwcx module. We discovered that the PWCX module reduced the entropy that the webcams provided. The PWCX module, when loaded, made webcams a poorer entropy source.
LavaRnd used the entropy provided by the actual hardware. Our analysis showed that PWCX was in effect "faking" the larger image sizes by taking, say the true 160x120 pixel CCD output and expanding it to something like 640x480. The expansion was as if a 2D smoothing function (such as a 2D spline?) filled in the pixels in between. Each of the original 160x120 hardware pixels was turned into a 4x4 pixel grid where the edges of the grid were adjusted to fit better with neighboring 4x4 pixel grids. The PWCX appeared to support a higher frame rate because the PWCX module "decompressed" the true hardware pixels and filled in the pseudo-pixels on the other side of the USB wire.
We discovered the PWCX effect while taking entropy measurements of webcam frames. Using PWC alone in 160x120 mode, the webcam produced slightly more entropy than 640x480 PWCX mode. The PWCX module was not adding real image data to webcam frames, it was just smoothing and filling in data that looked good enough to a human. However, PWCX could not fool the math ... :-)
The PWC maintainer says on his web site:
The PWC maintainer's position appears to be that if you cannot use PWCX, then PWC is worthless. From LavaRnd's point of view, PWCX (the binary only module) adds no value and in some ways reduces the Logitech QuickCam's value as an entropy source.
We (LavaRnd) do not want to take sides in this PWC/PWCX kernel dispute. If this posting appears that way, then we apologize. The PWC folks have been mostly patient with our unusual use of their webcam modules. The Linux kernel folks have provided us with a wonderful platform for LavaRnd. As for ourselves, we put a lot of time into helping end users use the PWC module in older kernels.
Here is our advice request:
The LavaRnd project would like to see the PWC (open source) module remain in the Linux Kernel. We would like the Linux kernel folk to not honor the maintainer's request to remove everything. We want the support of PWC without PWCX to continue in the Linux Kernel. What is the best was to make this position / request known to the key Kernel people in the hopes they will PWC as part of Linux?
And does every chunk of the Linux Kernel need an active maintainer? Could PWC remain in the Linux Kernel without the original maintainer's support or would someone such as ourselves need to step up and offer to maintain it?
chongo (was here)