Re: [PATCH 1/2] serial: 8250: enable SERIAL_MCTRL_GPIO by default.
From: Andy Shevchenko
Date: Tue Jun 05 2018 - 06:01:02 EST
On Mon, 2018-06-04 at 20:57 +0200, Giulio Benetti wrote:
> Il 04/06/2018 13:49, Andy Shevchenko ha scritto:
> > On Fri, 2018-06-01 at 16:11 +0200, Giulio Benetti wrote:
> > > It can be useful to override 8250 mctrl lines with gpios, for rts
> > > on
> > > rs485 for example, when rts is not mapped correctly to HW RTS pin.
> > >
> > > Enable SERIAL_MCTRL_GPIO by default.
> > >
> >
> > Unfortunately NAK, see
> >
> > commit 5db4f7f80d165fc9725f356e99feec409e446baa
> > Author: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
> > Date: Tue Aug 16 15:06:54 2016 +0300
> >
> > Revert "tty/serial/8250: use mctrl_gpio helpers"
> >
> > for the details.
> >
> > I would love to see a solution that will satisfy everyone, though I
> > have
> > only means to test proposals for now.
>
> Thanks for pointing me that.
> I would try to solve serial breakage on intel with already extisting
> patches dropping this one.
> I'm going to try.
>
> I can't understand if it's enough using qemu x86 to reproduce the bug.
> If so I'm going to debug and check what makes driver to fail.
You need to provide an ACPI table with UART contains GpioInt() or
GpioIo() resource in it.
Where GPIO number is a number of pin related to UART's RxD.
> Do you think it makes sense? Would it be accepted after bug fixing?
I can test on our hardware. Can't say about the rest, though.
--
Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Intel Finland Oy