[PATCH] Revert "serial: amba-pl011: fix incorrect integer size in pl011_fifo_to_tty()"
Dave P Martin
Dave.Martin at arm.com
Fri Oct 23 09:02:46 PDT 2015
On Fri, Oct 23, 2015 at 10:37:49AM -0500, Timur Tabi wrote:
> On 10/23/2015 08:34 AM, Dave P Martin wrote:
> >Well, I'm not saying there's definitely no kernel bug, but I can't see
> >how the patch should cause it. It may be triggering a latent bug
> >somewhere else in the driver than hasn't been biting us before, however.
> Fair enough.
> >!CREAD is the most obvious cause, so that should definitely be ruled
> >out first. If CREAD is clear, we need to figure out why...
> So I tested this by booting to my console, and then typing in:
> stty -cread
> and when I did that, the console ignored all input.
> I do admit that since !CREAD has been ignored for so many reason, it
> could be that a lot of userspaces will suddenly have broken
I'm pretty sure CREAD should default to enabled, and that usually
software won't modify it.
Assuming that this is indeed the problem, it's possible that another bug
in the pl011 driver is wrongly clearing this flag. Sadly I don't have
time to look at the code again just now ... :(
Could be interesting to stick some BUG_ON(!CREAD) in the driver to
try and track down where that's coming from.
 See serial_core.c:uart_register_driver(),
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