On 11 September 2015 at 15:22, Kishon Vijay Abraham I <kishon@xxxxxx> wrote:
> Hi Ulf,
>
> On Friday 11 September 2015 06:11 PM, Ulf Hansson wrote:
>> As mmc_claim_host() invokes pm_runtime_get_sync() for the mmc host device,
>> it's important that the host is kept claimed for *all* accesses to it via
>> the host_ops callbacks.
>>
>> In some code paths for SDIO, particularly related to the PM support,
>> mmc_power_off|up() is invoked without keeping the host claimed. Let's fix
>> these.
>>
>> Moreover, mmc_start|stop_host() also invokes mmc_power_off|up() without
>> claiming the host, let's fix these as well.
>>
>> Signed-off-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
>> ---
>> drivers/mmc/core/core.c | 6 ++++++
>> drivers/mmc/core/sdio.c | 20 +++++++++++++++-----
>> 2 files changed, 21 insertions(+), 5 deletions(-)
>>
> .
> .
> <snip>
> .
> .
>> int mmc_power_save_host(struct mmc_host *host)
>> diff --git a/drivers/mmc/core/sdio.c b/drivers/mmc/core/sdio.c
>> index b91abed..95bc101 100644
>> --- a/drivers/mmc/core/sdio.c
>> +++ b/drivers/mmc/core/sdio.c
>> @@ -897,11 +897,10 @@ static int mmc_sdio_pre_suspend(struct mmc_host *host)
>> */
>> static int mmc_sdio_suspend(struct mmc_host *host)
>> {
>> - if (mmc_card_keep_power(host) && mmc_card_wake_sdio_irq(host)) {
>> - mmc_claim_host(host);
>> + mmc_claim_host(host);
>> +
>> + if (mmc_card_keep_power(host) && mmc_card_wake_sdio_irq(host))
>> sdio_disable_wide(host->card);
>> - mmc_release_host(host);
>> - }
>>
>> if (!mmc_card_keep_power(host)) {
>> mmc_power_off(host);
>> @@ -910,6 +909,8 @@ static int mmc_sdio_suspend(struct mmc_host *host)
>> mmc_retune_needed(host);
>> }
>>
>> + mmc_release_host(host);
>> +
>> return 0;
>> }
>>
>> @@ -1018,15 +1019,24 @@ out:
>> static int mmc_sdio_runtime_suspend(struct mmc_host *host)
>> {
>> /* No references to the card, cut the power to it. */
>> + mmc_claim_host(host);
>> mmc_power_off(host);
>> + mmc_release_host(host);
>> +
>> return 0;
>> }
>>
>> static int mmc_sdio_runtime_resume(struct mmc_host *host)
>> {
>> + int ret;
>> +
>> /* Restore power and re-initialize. */
>> + mmc_claim_host(host);
>> mmc_power_up(host, host->card->ocr);
>> - return mmc_sdio_power_restore(host);
>> + ret = mmc_sdio_power_restore(host);
>
> IIUC, this will cause mmc_claim_host to be invoked twice since
> mmc_sdio_power_restore also invokes mmc_claim_host. I'm not sure if this
> will have undesired side effects.
That's not a problem, mmc_claim_host() handles that. As long it's the
same running context that tries to claim the host it will allow it.
Kind regards
Uffe
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