Re: Regression since 4a96895f74c9633b51427fd080ab70fa62b65bc4

[Yegor Yefremov <yegorslists@googlemail.com>]

Hi Nuno,

On Thu, Oct 17, 2019 at 3:34 PM Yegor Yefremov
<yegorslists@googlemail.com> wrote:
>
> Hi Nuno,
>
> On Thu, Oct 17, 2019 at 11:19 AM Nuno Gonçalves <nunojpg@gmail.com> wrote:
> >
> > Hi Yegor,
> >
> > I'm not sure if by your previous message you think I have some kind of
> > hardware or DT issue or if this is being handled as a regression.
>
> There were some upstreamed fixes recently. See commits [1], [2]. Also,
> make sure DMA for OMAP-8250 driver is disabled. Let me know if RTS/CTS
> is working as expected on am335x. See this discussion [3].
>
> [1] https://marc.info/?l=linux-kernel&m=157037963426476&w=2
> [2] https://marc.info/?l=linux-kernel&m=157037964726483&w=2
> [3] https://marc.info/?l=linux-omap&m=157018333915769&w=2

could you already try at least 5.4-rc4 and test whether the hardware
flow control is fixed for am335x and your application?

Regards,
Yegor

> > Thanks,
> > Nuno
> >
> > On Tue, Oct 1, 2019 at 11:03 PM Nuno Gonçalves <nunojpg@gmail.com> wrote:
> > >
> > > Yes, I remember seeing those warnings.
> > >
> > > On Tue, Oct 1, 2019 at 10:02 PM Yegor Yefremov
> > > <yegorslists@googlemail.com> wrote:
> > > >
> > > > Hi Nuno,
> > > >
> > > > On Sun, Sep 29, 2019 at 8:46 AM Nuno Gonçalves <nunojpg@gmail.com> wrote:
> > > > >
> > > > > I have since found that I am affected by two apparently different
> > > > > regressions since 5.3.
> > > > >
> > > > > 4a96895f74c9633b51427fd080ab70fa62b65bc4 is only confirmed to affect
> > > > > me on a omap8250 where the issue is that there are a few char errors
> > > > > every few seconds. I can't confirm if chars are added, removed or
> > > > > changed, for now I only can confirm my state machine looses tracking.
> > > >
> > > > Can you see kernel warnings about an overrun on OMAP UART?
> > > >
> > > > > I will make a separate report from the problem identified on sunxi.
> > > > >
> > > > > On Sat, Sep 28, 2019 at 7:59 AM Nuno Gonçalves <nunojpg@gmail.com> wrote:
> > > > > >
> > > > > > On 32 bit arm platforms (am335x and sunxi) I get unexpected bytes on
> > > > > > serial ports after this commit.
> > > > > >
> > > > > > I use CTS (so: for input flow control).
> > > > > >
> > > > > > I've observed two different issues, one where I get just a few missed
> > > > > > or added bytes about once a minute, and another where I get totally
> > > > > > unexpected chars until I reopen the port.
> > > > > >
> > > > > > I will have a hard time to analyse and give a better description of
> > > > > > how exactly the port is failing, so maybe you have a idea of what is
> > > > > > the issue with this patch.
> > > > > >
> > > > > > I've reverted this on top of 5.3.1 and consistently got the issue fixed.
> > > > > >
> > > > > > Thanks,
> > > > > > Nuno
> > > > > >
> > > > > > commit 4a96895f74c9633b51427fd080ab70fa62b65bc4
> > > > > > Author: Yegor Yefremov <yegorslists@googlemail.com>
> > > > > > Date:   Thu Jun 20 08:24:20 2019 +0200
> > > > > >
> > > > > >     tty/serial/8250: use mctrl_gpio helpers
> > > > > >
> > > > > >     This patch permits the usage for GPIOs to control
> > > > > >     the CTS/RTS/DTR/DSR/DCD/RI signals.
> > > > > >
> > > > > >     Changed by Stefan:
> > > > > >     Only call mctrl_gpio_init(), if the device has no ACPI companion device
> > > > > >     to not break existing ACPI based systems. Also only use the mctrl_gpio_
> > > > > >     functions when "gpios" is available.
> > > > > >
> > > > > >     Use MSR / MCR <-> TIOCM wrapper functions.
> > > > > >
> > > > > >     Signed-off-by: Yegor Yefremov <yegorslists@googlemail.com>
> > > > > >     Signed-off-by: Stefan Roese <sr@denx.de>
> > > > > >     Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> > > > > >     Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
> > > > > >     Tested-by: Yegor Yefremov <yegorslists@googlemail.com>
> > > > > >     Cc: Mika Westerberg <mika.westerberg@linux.intel.com>
> > > > > >     Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> > > > > >     Cc: Giulio Benetti <giulio.benetti@micronovasrl.com>
> > > > > >     Cc: Yegor Yefremov <yegorslists@googlemail.com>
> > > > > >     Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> > > > > >     Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>