[PATCH 1/2 v1] davinci: support disabling modem status interrupts on SOC UARTS

Manjunathappa, Prakash prakash.pm at ti.com
Tue Jan 11 10:43:03 EST 2011

On Tue, Jan 11, 2011 at 18:12:25, Michael Williamson wrote:
> [...]
> This was pretty much what the original patch I had proposed did.  There are
> actually two termios flags that cause MS interrupts to be enabled by the
> driver, CLOCAL (disabled) or CRTSCTS (enabled).  I observed that some
> process after the kernel had completed booting (getty, I think)
> was calling set_termios with CLOCAL disabled (not CRTSCTS enabled).  I could
> probably alter the getty args to work around it, but it's a bit of a hole to
> not have something in the kernel to preclude sending the OS to "interrupt 
> hell".
> Is there another way to accomplish what you are suggesting that is different
> from the original patch?
> Thanks for the comments.
> -Mike
> Background: The original patch (not accepted) is here
> https://patchwork.kernel.org/patch/442671/
> This kicked a second email thread:
> http://marc.info/?l=linux-serial&m=129409970003827&w=4
> From that thread, it was suggested to add a port flag to the driver
> flags structure for disabling MS interrupts.
> Driver Tweak patch (not accepted):
> https://patchwork.kernel.org/patch/450771/
> From that thread, it was suggested to override the I/O methods and hide
> the problem back in the platform code (this patch).
> All three proposed patches work for me.  I'd gladly submit a fourth if
> suggested -- this problem pretty much kills a couple of platform
> configurations we are working on...
> > Thanks,
> > Prakash
> > 
Thanks for clarifying. Looks like this is what we can do as of now.


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