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

Paul Walmsley paul at
Fri Feb 3 22:16:08 EST 2012

On Sat, 4 Feb 2012, NeilBrown wrote:

> On Fri, 3 Feb 2012 19:06:19 -0700 (MST) Paul Walmsley <paul at> wrote:
> > 
> > Here's a patch that helps.  It seems to work down to an 
> > autosuspend_delay_ms of 1 ms.  Without it, the best I can get is 8 ms.
> > 
> > Of course, ideally it should work fine at autosuspend_delay_ms = 0, so 
> > likely there's some other infelicity that we're currently missing.
> > 
> > Neil, care to give this a test and confirm it on your setup?
> Yes, that seems to make the output corruption go away.

Cool, thanks for the test :-)

> Even with small autosuspend_delay_ms down to 0 it doesn't corrupt output,
> but as the first input byte is corrupted, I cannot really type with those
> setting (so I ssh to gain control again).

Could you try pasting in a buffer from another window?  If I paste in the 
buffer at the bottom of this message a few times, I see some output 

- Paul

cat  /sys/devices/platform/omap/omap_uart.2/power/autosuspend_delay_ms
echo 0 > /sys/devices/platform/omap/omap_uart.2/power/autosuspend_delay_ms
cat /proc/interrupts

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