Re: [PATCH 0/4] serial: qcom-geni: fix console shutdown hang

[Srinivas Kandagatla]

On 07/03/2023 17:03, Johan Hovold wrote:
> On Tue, Mar 07, 2023 at 05:47:27PM +0100, Bartosz Golaszewski wrote:
> > On Tue, 7 Mar 2023 at 17:44, Bartosz Golaszewski
> > <bartosz.golaszewski@xxxxxxxxxx> wrote:
> > > On Tue, 7 Mar 2023 at 17:43, Johan Hovold <johan+linaro@xxxxxxxxxx> wrote:
> > > > This series fixes some of the fallout after a recent series adding
> > > > support for DMA transfers to the Qualcomm geni serial driver.
> > > >
> > > > Most importantly it fixes a hang during reboot when using a serial
> > > > console and the getty is stopped during reboot.
> > > >
> > > > Doug just posted an equivalent fix here:
> > > >
> > > >          https://lore.kernel.org/lkml/20230307073155.1.Iaab0159b8d268060a0e131ebb27125af4750ef99@changeid
> > > >
> > > > but the commit message only mentions the regression with respect to
> > > > kgdb, which is not as widely used serial consoles generally, so I
> > > > figured I'd post my version for completeness.
> > > >
> > > > Either version of that fix should address the immediate regression, but
> > > > fixing the underlying problems which have been there since the driver
> > > > was first merged is going to be a bit more involved.
> > > >
> > > > The rest of the series fixes a few bugs in the new DMA support that I
> > > > found while investigating the console regression.
> > > >
> > > > Johan
> > > >
> > > >
> > > > Johan Hovold (4):
> > > >    serial: qcom-geni: fix console shutdown hang
> > > >    serial: qcom-geni: fix DMA mapping leak on shutdown
> > > >    serial: qcom-geni: fix mapping of empty DMA buffer
> > > >    serial: qcom-geni: drop bogus uart_write_wakeup()
> > > >
> > > >   drivers/tty/serial/qcom_geni_serial.c | 11 +++++++----
> > > >   1 file changed, 7 insertions(+), 4 deletions(-)
> > > >
> > > > --
> > > > 2.39.2
> > >
> > > Hey Johan,
> > >
> > > Douglas and Srini beat you to these fixes but thanks!
>
> > Nevermind, I read your other message now. And also patch 3/4 looks right.
>
> Heh, this hang has been in linux-next for over a month and I've
> actively tried to not spend time on investigating it in the hope that
> someone else would be beat me to it before I moved to 6.3-rc. :)
>
> Obviously I may be a bit biased, but I prefer this series over the
> alternate fixes as the commit messages are a bit more complete and my
> version of the empty DMA buffer fix is a bit cleaner.

I don't mind, as long as the bugs are fixed.


--srini
> Johan