Bug#630593: The Intel parport bug
found 630593 linux-2.6/3.1.1-1
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Leopold Palomo-Avellaneda wrote:
> I don't have any hope that it would be solved in the linux kernel, but at
> least in the debian kernel it could be applied.
So, it seems that "the Intel bug" is that Intel's 82091 is not
advertised to implement (and does not implement?) the timeout bit in
the ECR register. There are various possible approaches to work
around that.
The current code in mainline that tries to detect these chipsets is
nonsense. Even so, the suggested patch that rips it out would have a
chance of introducing regressions and probably should not be applied
unless someone finds a way to test it widely. There were two
alternative approaches suggested in the upstream discussion, intended
not to suffer from the same problem[1][2] (caveat: I have not
sanity-checked the second one).
In other words, we are between steps 1 and 2 of the short story
described earlier in this bug log. The next step is to take the
feedback received into account and propose a new patch. My only
additional advice is that [3] seems to be a nice reference for getting
accustomed to Linux internals.
If I were writing it, I would rip out the code marked "Check for Intel
bug" and use a kernel parameter to decide whether to assume broken EPP
support, defaulting to true. Simpler, more robust, and hard to object
to.
Thanks again and hope that helps,
Jonathan
[1] http://thread.gmane.org/gmane.linux.kernel/1191731
[2] http://thread.gmane.org/gmane.linux.kernel/1192024/focus=1746
[3] http://lwn.net/Kernel/LDD3/
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