On Monday 20 August 2007, Bjorn Helgaas wrote:

On Saturday 18 August 2007 01:07:55 am Andrey Borzenkov wrote:

quoted

This is related to thread "2.6.22-rc: regression: no irda0 interface
(2.6.21 was OK), smsc does not find chip" but it is already way too
overloaded.

In 2.6.23 smsc-ircc2 fails to initialize IrDA controller. Apparently
because it by default is using the same IO port as ttyS3 and this is now
claimed by 8250.

8250 should have claimed ttyS3 in 2.6.21 and earlier.  So from
the 8250 point of view, 2.6.21 and 2.6.23 should behave the same.

I only know that this worked in 2.6.21. I remind that previous regression was 
post-2.6.21 which obviously implies that it did work ...

For reference I attach dmesg from 2.6.21. I do not see any ttyS3 there ...

From the smsc-ircc2 point of view, 2.6.21 and 2.6.23 should work
the same except for the additional quirk_smc_enable().  If
2.6.23 is worse than 2.6.21, please try removing the body of
quirk_smc_enable() and see whether that makes 2.6.23 as good
as 2.6.21.

This worked in 2.6.22 with the same quirks. I will test without later but I 
fail to see how they are related.

For smsc-ircc2, 2.6.23 is definitely a regression from 2.6.22,
because 8250 stayed out of the way in 2.6.22.  But we had to
revert 8250 back to the 2.6.21 behavior because the change
swapped ttyS0 and ttyS1 on some machines, so we just have to
live with that 8250/smsc-ircc2 conflict for the time being.

This worked in 2.6.21 and 2.6.22 (and earlier BTW). So if you just had revert 
to 2.6.21 it would have worked. Something else changed.