ep93xx irq-vic regression

Florian Fainelli florian at openwrt.org
Sun Mar 17 10:48:19 EDT 2013


On Sunday 17 March 2013 11:06:29 Ryan Mallon wrote:
[snip]
> >> From: H Hartley Sweeten <hsweeten at visionengravers.com>
> >> Subject: [PATCH] arm: ep93xx: fix wait for UART FIFO to be empty
> >>
> >> commit 210dce5f "ARM: ep93xx: properly wait for UART FIFO to be empty"
> >>
> >> Removed the timeout loop while waiting for the uart transmit fifo to
> >> empty. Some bootloaders leave the uart in a state where there might
> >> be bytes in the uart that are not transmitted when execution is handed
> >> over to the kernel. This results in a deadlocked system while waiting
> >> for the fifo to empty.
> >>
> >> Add back the timeout wait to prevent the deadlock.
> >>
> >> Increase the wait time to hopefully prevent the decompressor corruption
> >> that lead to commit 210dce5f. This corruption was probably due to a
> >> slow uart baudrate. The 10* increase in the wait time should be enough
> >> for all cases.
> > 
> > Ok, your solution seems like it would work, when I come accross this bug I 
> > initially ended up doing the same thing and incrementing the number of 
> > iterations in the loop. I was not quite happy with that as it would still 
be 
> > highly depending on the clocking. Anyway, sorry for breaking your system 
with 
> > this commit.
> 
> 
> Do you want to add an Acked/Reviewed-by Florian? I'll queue this
> up in my tree if you are happy with it.

Yes, I just re-tested with 10000 as a loop value, and it fixes the corruption I 
was seeing, you can add my Acked-by: Florian Fainelli <florian at openwrt.org>

Thanks to both of you!
-- 
Florian



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