+ Linus
On 29 May 2016 at 09:04, Chen-Yu Tsai <wens@xxxxxxxx> wrote:
> When IS_ERR_VALUE was removed from the mmc core code, it was replaced
> with a simple not-zero check. This does not work, as the value checked
> is the return value for mmc_select_bus_width, which returns the set
> bit width on success. This made eMMC modes higher than HS-DDR unusable.
>
> Fix this by checking for a positive return value instead.
>
> Fixes: 287980e49ffc ("remove lots of IS_ERR_VALUE abuses")
> Cc: Arnd Bergmann <arnd@xxxxxxxx>
> Signed-off-by: Chen-Yu Tsai <wens@xxxxxxxx>
> ---
> 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 c984321d1881..aafb73d080ca 100644
> --- a/drivers/mmc/core/mmc.c
> +++ b/drivers/mmc/core/mmc.c
> @@ -1276,7 +1276,7 @@ static int mmc_select_hs200(struct mmc_card *card)
> * switch to HS200 mode if bus width is set successfully.
> */
> err = mmc_select_bus_width(card);
> - if (!err) {
> + if (err > 0) {
> val = EXT_CSD_TIMING_HS200 |
> card->drive_strength << EXT_CSD_DRV_STR_SHIFT;
> err = __mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
> @@ -1583,7 +1583,7 @@ static int mmc_init_card(struct mmc_host *host, u32 ocr,
> } else if (mmc_card_hs(card)) {
> /* Select the desired bus width optionally */
> err = mmc_select_bus_width(card);
> - if (!err) {
> + if (err > 0) {
As pointed out in the review by Björn, to restore the old behaviour we
should check for "err >= 0".
No need to send a new patch, I can amend the current version.
> err = mmc_select_hs_ddr(card);
> if (err)
> goto free_card;
> --
> 2.8.1
>
Finally, I am a little concerned about the commit 287980e49ffc
("remove lots of IS_ERR_VALUE abuses") which introduced this
regression.
Surprisingly the IS_ERR_VALUE():s aren't being replaced by equivalent
checks, so perhaps there a more regressions. Moreover, I wonder why I
wasn't being on cc/to list when this patch was submitted a few days
ago, perhaps my review could prevented the regression from even
happen.
Anyway, let's fix this now! I will pick up $subject patch as fix asap...
and Arnd, can you please double-check that the commit 287980e49ffc
doesn’t seems to regress anything else!?
Kind regards
Uffe
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