Re: [PATCH v2] serial: amba-pl011: Fix RX stall when DMA is used

[Linus Walleij]

On Wed, Nov 13, 2024 at 10:26 AM Kartik Rajput <kkartik@xxxxxxxxxx> wrote:

> Function pl011_throttle_rx() calls pl011_stop_rx() to disable RX, which
> also disables the RX DMA by clearing the RXDMAE bit of the DMACR
> register. However, to properly unthrottle RX when DMA is used, the
> function pl011_unthrottle_rx() is expected to set the RXDMAE bit of
> the DMACR register, which it currently lacks. This causes RX to stall
> after the throttle API is called.
>
> Set RXDMAE bit in the DMACR register while unthrottling RX if RX DMA is
> used.
>
> Fixes: 211565b10099 ("serial: pl011: UPSTAT_AUTORTS requires .throttle/unthrottle")
> Cc: <stable@xxxxxxxxxxxxxxx>
> Signed-off-by: Kartik Rajput <kkartik@xxxxxxxxxx>

Looks right to me, thanks Kartik!
Reviewed-by: Linus Walleij <linus.walleij@xxxxxxxxxx>

Yours,
Linus Walleij