Stephen Clark wrote:
Bill Davidsen wrote:
Stephen Clark wrote:
Bill Davidsen wrote:
Alan Cox wrote:
it seems broken to manipulate xfer_mask after returning from the
driver's ->mode_filter hook.
this patch is more than just a speed-limited warning printk, afaics
I actually suggested that order because the only way the printk
can be
done correctly is for it to be the very last test made. Since the
mode
filter is not told what mode will be used but just subtracts modes
that
are not allowed this should be safe.
Far better to have a drive which works slowly than one which works
unreliably.
That would be true if the 40 wire detection was 100% accurate!
The statement is completely correct, even though the detection may
not be. ;-)
With the current set(s) of patches to do better detection, cable
evaluation should be better. But even if not, a slow system is more
useful than one which doesn't work, crashes because of swap i/o
errors, etc.
I have had problems with cable detection on my previous laptop and my
current laptop. It almost made
my systems unusable. On my current laptop I was getting a thruput of a
little over 1 mbps instead
of the 44 mbps I get with udma set to the correct value. It took hours
to upgrade my laptop from
fc5 to fc6 because of this mis detection.
As far as I can see, if you are getting that low a speed, you have other
problems. I have a system with old slow drives which are really on a 40
pin cable, and they run at UDMA(33). One of the experts in this can
undoubtedly tell us more, but your system should run faster than that,
mine does, and I really HAVE a 40 pin cable (and drive).
If your system drops to PIO modes, I doubt cable is the only issue, I
think there are other issues (acpi comes to mind).
--
bill davidsen <davidsen@xxxxxxx>
CTO TMR Associates, Inc
Doing interesting things with small computers since 1979
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