On 14.03.2022 11:54, Ulf Hansson wrote:
> On Thu, 3 Mar 2022 at 17:45, Ulf Hansson <ulf.hansson@xxxxxxxxxx> wrote:
>>
>> In the error path of mmc_select_hs200() we are trying our best to restore
>> the card/host into a valid state. This makes sense, especially if we
>> encounter a simple switch error (-EBADMSG). However, rather than then
>> continue with using the legacy speed mode, let's try the other better speed
>> modes first. Additionally, let's update the card->mmc_avail_type to avoid
>> us from trying a broken HS200 mode again.
>>
>> In an Amlogic S905W based TV box where the switch to HS200 mode fails for
>> the eMMC, this allows us to use the eMMC in DDR mode in favor of the legacy
>> mode, which greatly improves the performance.
>>
>> Suggested-by: Heiner Kallweit <hkallweit1@xxxxxxxxx>
>> Signed-off-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
>
> Heiner, does this solve your problems? Can you perhaps run some tests
> at your side to see how it works for you?
>
Tested-by: Heiner Kallweit <hkallweit1@xxxxxxxxx>
> Kind regards
> Uffe
>
Heiner
>> ---
>> drivers/mmc/core/mmc.c | 16 +++++++++++++---
>> 1 file changed, 13 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
>> index 141f851c9f58..6e7db45cb8e0 100644
>> --- a/drivers/mmc/core/mmc.c
>> +++ b/drivers/mmc/core/mmc.c
>> @@ -1518,13 +1518,23 @@ static int mmc_select_timing(struct mmc_card *card)
>> if (!mmc_can_ext_csd(card))
>> goto bus_speed;
>>
>> - if (card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS400ES)
>> + if (card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS400ES) {
>> err = mmc_select_hs400es(card);
>> - else if (card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS200)
>> + goto out;
>> + }
>> +
>> + if (card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS200) {
>> err = mmc_select_hs200(card);
>> - else if (card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS)
>> + if (err == -EBADMSG)
>> + card->mmc_avail_type &= ~EXT_CSD_CARD_TYPE_HS200;
>> + else
>> + goto out;
>> + }
>> +
>> + if (card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS)
>> err = mmc_select_hs(card);
>>
>> +out:
>> if (err && err != -EBADMSG)
>> return err;
>>
>> --
>> 2.25.1
>>
