patch "tty: serial: OMAP: ensure FIFO levels are set correctly in non-DMA" added to tty tree

NeilBrown neilb at suse.de
Fri Feb 3 23:17:38 EST 2012


On Fri, 3 Feb 2012 20:56:07 -0700 (MST) Paul Walmsley <paul at pwsan.com> wrote:

> On Sat, 4 Feb 2012, NeilBrown wrote:
> 
> > I have to set autosuspend_delay_ms for omap_uart.3 as well before the
> > behaviour is significant.
> > But then I see no output corruption.  Lots of input corruption of course but
> > the output looks fine.
> 
> OK.  Is the input corruption at the beginning of the pasted buffer, or the 
> middle?  And this is with CPUIdle enabled?
> 
> With CPUIdle disabled here, what I thought was output corruption occurs in 
> the middle of the pasted buffer occasionally.  But it might be input 
> corruption, if the CPU manages to empty the RX FIFO while the TX FIFO is 
> empty.
> 
> 
> - Paul

Yes, cpu-idle is enabled.

I think corruption is mostly early, though it isn't very consistent.

e.g.

# C!jHhzys/Y?omap/omap_uart.2/power/autosuspend_delay_ms
-bash: !jHhzys/Y?omap/omap_uart.2/power/autosuspend_delay_ms: event not found
# echo 0 > /sys/devices/platFK/////mpWWt.]au%e_mHHHhQ 5
-bash: /sys/devices/platFK/////mpWWt.]au%e_mHHHhQ: No such file or directory


NeilBrown
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