- Seungwon (due to bouncing email)
On 13 February 2017 at 12:46, Anssi Hannula <anssi.hannula@xxxxxxxxxx> wrote:
> Commit 577fb13199b1 ("mmc: rework selection of bus speed mode")
> refactored bus width selection code to mmc_select_bus_width().
>
> However, it also altered the behavior to not call the selection code in
> non-high-speed modes anymore.
>
> This causes 1-bit mode to always be used when the high-speed mode is not
> enabled, even though 4-bit and 8-bit bus are valid bus widths in the
> backwards-compatibility (legacy) mode as well (see e.g. 5.3.2 Bus Speed
> Modes in JEDEC 84-B50). This results in a significant regression in
> transfer speeds.
>
> Fix the code to allow 4-bit and 8-bit widths even without high-speed
> mode, as before.
>
> Tested with a Zynq-7000 PicoZed 7020 board.
>
> Signed-off-by: Anssi Hannula <anssi.hannula@xxxxxxxxxx>
> Cc: Seungwon Jeon <tgih.jun@xxxxxxxxxxx>
> Cc: <stable@xxxxxxxxxxxxxxx>
> Fixes: 577fb13199b1 ("mmc: rework selection of bus speed mode")
Thanks, applied for fixes!
Kind regards
Uffe
> ---
> drivers/mmc/core/mmc.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
> index b61b52f9..0fccca0 100644
> --- a/drivers/mmc/core/mmc.c
> +++ b/drivers/mmc/core/mmc.c
> @@ -1706,10 +1706,10 @@ static int mmc_init_card(struct mmc_host *host, u32 ocr,
> err = mmc_select_hs400(card);
> if (err)
> goto free_card;
> - } else if (mmc_card_hs(card)) {
> + } else {
> /* Select the desired bus width optionally */
> err = mmc_select_bus_width(card);
> - if (err > 0) {
> + if (err > 0 && mmc_card_hs(card)) {
> err = mmc_select_hs_ddr(card);
> if (err)
> goto free_card;
> --
> 2.8.3
>
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