On 2014/8/5 4:12, Arend van Spriel wrote:
> On 08/04/14 18:52, Russell King - ARM Linux wrote:
>> On Tue, Aug 05, 2014 at 12:36:49AM +0800, Fu, Zhonghui wrote:
>>> Hi, Arend
>>>
>>> I investigated this issue, and its root cause is still that sdio
>>> controller can't receive interrupts from WiFi chip on sdio bus when
>>> sdio controller is in runtime suspend status. I am running 3.16-rc5
>>> linux kernel on ASUS T100TA tablet, and using sdhci-acpi driver.
>>
>> That's the root cause. I fixed this with the Freescale i.MX SD driver
>> which is now able to report pending SDIO interrupts while runtime PM
>> suspended.
>>
>> Other host drivers probably need fixing too, or having runtime PM
>> disabled on them - if you can't receive SDIO interrupts while runtime
>> PM suspended, then entering runtime PM while you have a SDIO device
>> attached is a bug.
>>
>> This is something for the MMC people to deal with rather than Arend.
>
> Occasionally, the itch is there to fix mmc code, but this looks a bit tricky.
> The fun starts in sdio.c:mmc_attach_sdio():
>
> /*
> * Enable runtime PM only if supported by host+card+board
> */
> if (host->caps & MMC_CAP_POWER_OFF_CARD) {
> /*
> * Let runtime PM core know our card is active
> */
> err = pm_runtime_set_active(&card->dev);
> if (err)
> goto remove;
>
> /*
> * Enable runtime PM for this card
> */
> pm_runtime_enable(&card->dev);
> }
>
> The comment above the if statement seems to be stating the right idea, but
> the code only looks at the host controller capability flags.
Yes, this code section is not implemented as its comments.
Thanks,
Zhonghui
>
> Regards,
> Arend
>
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