On 10/23/2015 11:02 AM, Dave P Martin wrote:
I'm pretty sure CREAD should default to enabled[1], 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 ...:(
Perhaps, but !CREAD is definitely broken without this patch. So if the
driver really is clearing CREAD somewhere else, then that's where the
real bug is.
Could be interesting to stick some BUG_ON(!CREAD) in the driver to
try and track down where that's coming from.
CREAD is disabled by default when opening the console. You need to
explicitly set it in the termios structure. I can easily believe that
Huang's rootfs is just forgetting to set that bit because for the last
five years, it didn't matter.
Huang,
In the beginning of pl011_set_termios() and sbsa_uart_set_termios(),
please add this code:
BUG_ON(!(termios->c_cflag & CREAD));
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