On 6 December 2012 16:25, Subhash Jadavani <[email protected]> wrote:
>
> On 12/6/2012 4:03 PM, Ulf Hansson wrote:
>>
>> On 4 December 2012 12:36, Subhash Jadavani <[email protected]>
>> wrote:
>>>
>>> If SDIO keep power flag (MMC_PM_KEEP_POWER) is not set, card would
>>> be reinitialized during resume but as we are not resetting
>>> (CMD52 reset) the SDIO card during this reinitialization, card may
>>> fail to respond back to subsequent commands (CMD5 etc...).
>>>
>>> This change resets the card before the reinitialization of card
>>> during resume.
>>>
>>> Signed-off-by: Subhash Jadavani <[email protected]>
>>> ---
>>> drivers/mmc/core/sdio.c | 6 ++++--
>>> 1 files changed, 4 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/drivers/mmc/core/sdio.c b/drivers/mmc/core/sdio.c
>>> index 2273ce6..34ad4c8 100644
>>> --- a/drivers/mmc/core/sdio.c
>>> +++ b/drivers/mmc/core/sdio.c
>>> @@ -937,10 +937,12 @@ static int mmc_sdio_resume(struct mmc_host *host)
>>> mmc_claim_host(host);
>>>
>>> /* No need to reinitialize powered-resumed nonremovable cards */
>>> - if (mmc_card_is_removable(host) || !mmc_card_keep_power(host))
>>> + if (mmc_card_is_removable(host) || !mmc_card_keep_power(host)) {
>>> + sdio_reset(host);
>>> + mmc_go_idle(host);
>>
>> If the card has lost power, why is this needed? Could it be that the
>> host is not capable of cutting the power to card?
>
>
> Yes, the regulator powering the card is always on in this case which means
> SDIO VDD is not powered off during the suspend.
>
So in principle the host should be able to notify the protocol layer
about that mmc_card_keep_power will always be set somehow.
That could be a more proper way of solving this maybe? What do you think?
>
>>
>> It might be more safe to do this but I would like to understand more,
>> before you get my ack on this patch.
>>
>>> err = mmc_sdio_init_card(host, host->ocr, host->card,
>>> mmc_card_keep_power(host));
>>> - else if (mmc_card_keep_power(host) &&
>>> mmc_card_wake_sdio_irq(host)) {
>>> + } else if (mmc_card_keep_power(host) &&
>>> mmc_card_wake_sdio_irq(host)) {
>>> /* We may have switched to 1-bit mode during suspend */
>>> err = sdio_enable_4bit_bus(host->card);
>>> if (err > 0) {
>>> --
>>> --
>>> QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
>>> of Code Aurora Forum, hosted by The Linux Foundation
>>>
>>> --
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>>
>> Kind regards
>> Ulf Hansson
>
>
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