Re: [PATCH RFC 3/3] MIPS: AR7: ensure the port type's FCR value is used

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Mon, Jan 22, 2018 at 01:07:19PM +0000, James Hogan wrote:
> Hi stable maintainers,
> 
> On Sun, Oct 29, 2017 at 04:27:21PM +0100, Jonas Gorski wrote:
> > Since commit aef9a7bd9b67 ("serial/uart/8250: Add tunable RX interrupt
> > trigger I/F of FIFO buffers"), the port's default FCR value isn't used
> > in serial8250_do_set_termios anymore, but copied over once in
> > serial8250_config_port and then modified as needed.
> > 
> > Unfortunately, serial8250_config_port will never be called if the port
> > is shared between kernel and userspace, and the port's flag doesn't have
> > UPF_BOOT_AUTOCONF, which would trigger a serial8250_config_port as well.
> > 
> > This causes garbled output from userspace:
> > 
> > [    5.220000] random: procd urandom read with 49 bits of entropy available
> > ers
> >    [kee
> > 
> > Fix this by forcing it to be configured on boot, resulting in the
> > expected output:
> > 
> > [    5.250000] random: procd urandom read with 50 bits of entropy available
> > Press the [f] key and hit [enter] to enter failsafe mode
> > Press the [1], [2], [3] or [4] key and hit [enter] to select the debug level
> > 
> > Fixes: aef9a7bd9b67 ("serial/uart/8250: Add tunable RX interrupt trigger I/F of FIFO buffers")
> > Signed-off-by: Jonas Gorski <jonas.gorski@gmail.com>
> 
> Please can this patch be applied to stable branches 3.17+. It is now
> merged into mainline as commit 0a5191efe06b ("MIPS: AR7: ensure the port
> type's FCR value is used").
> 
> Commit b084116f8587 ("MIPS: AR7: Ensure that serial ports are properly
> set up") is a prerequisite for it to apply cleanly, but is already
> tagged for stable.

Now snuck into this round of stable -rc review :)

thanks,

greg k-h