Re: [PATCH 1/2] mmc: meson-gx: make replace WARN_ONCE with dev_warn_once about scatterlist offset alignment

[Ulf Hansson]

On Mon, 26 Apr 2021 at 19:56, Neil Armstrong <narmstrong@xxxxxxxxxxxx> wrote:
>
> Some drivers like ath10k can sometimg give an sg buffer with an offset whose alignment
> is not compatible with the Amlogic DMA descriptor engine requirements.
>
> Simply replace with dev_warn_once() to inform user this should be fixed to avoid
> degraded performance.
>
> This should be ultimately fixed in ath10k, but since it's only a performance issue
> the warning should be removed.
>
> Fixes: 79ed05e329c3 ("mmc: meson-gx: add support for descriptor chain mode")
> Reported-by: Christian Hewitt <christianshewitt@xxxxxxxxx>
> Signed-off-by: Neil Armstrong <narmstrong@xxxxxxxxxxxx>

Applied for fixes and by adding a stable tag, thanks!

Kind regards
Uffe


> ---
>  drivers/mmc/host/meson-gx-mmc.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/mmc/host/meson-gx-mmc.c b/drivers/mmc/host/meson-gx-mmc.c
> index b8b771b643cc..1c61f0f24c09 100644
> --- a/drivers/mmc/host/meson-gx-mmc.c
> +++ b/drivers/mmc/host/meson-gx-mmc.c
> @@ -258,7 +258,9 @@ static void meson_mmc_get_transfer_mode(struct mmc_host *mmc,
>         for_each_sg(data->sg, sg, data->sg_len, i) {
>                 /* check for 8 byte alignment */
>                 if (sg->offset % 8) {
> -                       WARN_ONCE(1, "unaligned scatterlist buffer\n");
> +                       dev_warn_once(mmc_dev(mmc),
> +                                     "unaligned sg offset %u, disabling descriptor DMA for transfer\n",
> +                                     sg->offset);
>                         return;
>                 }
>         }
> --
> 2.25.1
>