Re: [PATCH 2/8] serial: qcom-geni: fix false console tx restart

[Doug Anderson]

Hi,

On Mon, Sep 2, 2024 at 8:26 AM Johan Hovold <johan+linaro@xxxxxxxxxx> wrote:
>
> Commit 663abb1a7a7f ("tty: serial: qcom_geni_serial: Fix UART hang")
> addressed an issue with stalled tx after the console code interrupted
> the last bytes of a tx command by reenabling the watermark interrupt if
> there is data in write buffer. This can however break software flow
> control by re-enabling tx after the user has stopped it.
>
> Address the original issue by not clearing the CMD_DONE flag after
> polling for command completion. This allows the interrupt handler to
> start another transfer when the CMD_DONE interrupt has not been disabled
> due to flow control.
>
> Fixes: c4f528795d1a ("tty: serial: msm_geni_serial: Add serial driver support for GENI based QUP")
> Fixes: 663abb1a7a7f ("tty: serial: qcom_geni_serial: Fix UART hang")
> Cc: stable@xxxxxxxxxxxxxxx      # 4.17
> Signed-off-by: Johan Hovold <johan+linaro@xxxxxxxxxx>
> ---
>  drivers/tty/serial/qcom_geni_serial.c | 13 +++----------
>  1 file changed, 3 insertions(+), 10 deletions(-)

This seems reasonable. I guess this can end up causing a spurious
"done" interrupt to sometimes occur but that looks to be harmless.

Reviewed-by: Douglas Anderson <dianders@xxxxxxxxxxxx>