Re: [PATCH] serial: sh-sci: disable DMA for uart_console
From: Simon Horman
Date: Mon May 13 2019 - 07:44:02 EST
On Mon, May 13, 2019 at 01:13:16PM +0200, Geert Uytterhoeven wrote:
> Hi George,
> On Thu, May 9, 2019 at 4:44 PM George G. Davis <ggdavisiv@xxxxxxxxx> wrote:
> > As noted in commit 84b40e3b57ee ("serial: 8250: omap: Disable DMA for
> > console UART"), UART console lines use low-level PIO only access functions
> > which will conflict with use of the line when DMA is enabled, e.g. when
> > the console line is also used for systemd messages. So disable DMA
> > support for UART console lines.
> > Fixes: https://patchwork.kernel.org/patch/10929511/
> > Reported-by: Michael Rodin <mrodin@xxxxxxxxxxxxxx>
> > Cc: Eugeniu Rosca <erosca@xxxxxxxxxxxxxx>
> > Signed-off-by: George G. Davis <george_davis@xxxxxxxxxx>
> I think this makes sense. In addition to OMAP 8250, the same approach
> is used in the Mediatek 8250 and iMX serial drivers.
> Regardless, this is definitely better than removing the "dmas" properties
> from DT, as DT describes hardware, not usage policies.
> Anyone else with a comment?
Reviewed-by: Simon Horman <horms+renesas@xxxxxxxxxxxx>