Re: [PATCH v1 3/3] usb: phy: msm: Do not do runtime pm if the phy is not idle

[Srinivas Kandagatla <srinivas.kandagatla@linaro.org>]

On 30/06/14 18:56, Felipe Balbi wrote:
> On Mon, Jun 30, 2014 at 06:29:57PM +0100, Srinivas Kandagatla wrote:
>> Use case is when the phy is configured in host mode and a usb device is
>> attached to board before bootup. On bootup, with the existing code and
>> runtime pm enabled, the driver would decrement the pm usage count
>> without checking the current state of the phy. This pm usage count
>> decrement would trigger the runtime pm which than would abort the
>> usb enumeration which was in progress. In my case a usb stick gets
>> detected and then immediatly the driver goes to low power mode which is
>> not correct.
>>
>> log:
>> [    1.631412] msm_hsusb_host 12520000.usb: EHCI Host Controller
>> [    1.636556] msm_hsusb_host 12520000.usb: new USB bus registered, assigned bus number 1
>> [    1.642563] msm_hsusb_host 12520000.usb: irq 220, io mem 0x12520000
>> [    1.658197] msm_hsusb_host 12520000.usb: USB 2.0 started, EHCI 1.00
>> [    1.659473] hub 1-0:1.0: USB hub found
>> [    1.663415] hub 1-0:1.0: 1 port detected
>> ...
>> [    1.973352] usb 1-1: new high-speed USB device number 2 using msm_hsusb_host
>> [    2.107707] usb-storage 1-1:1.0: USB Mass Storage device detected
>> [    2.108993] scsi0 : usb-storage 1-1:1.0
>> [    2.678341] msm_otg 12520000.phy: USB in low power mode
>> [    3.168977] usb 1-1: USB disconnect, device number 2
>>
>> This issue was detected on IFC6410 board.
>>
>> This patch fixes the intial runtime pm trigger by checking the phy
>> state and decrementing the pm use count only when the phy state is IDLE.
>>
>> Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
>> ---
>>   drivers/usb/phy/phy-msm-usb.c | 4 +++-
>>   1 file changed, 3 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/usb/phy/phy-msm-usb.c b/drivers/usb/phy/phy-msm-usb.c
>> index 3bb559d..78cc870 100644
>> --- a/drivers/usb/phy/phy-msm-usb.c
>> +++ b/drivers/usb/phy/phy-msm-usb.c
>> @@ -1229,7 +1229,9 @@ static void msm_otg_sm_work(struct work_struct *w)
>>   			motg->chg_state = USB_CHG_STATE_UNDEFINED;
>>   			motg->chg_type = USB_INVALID_CHARGER;
>>   		}
>> -		pm_runtime_put_sync(otg->phy->dev);
>> +
>> +		if (otg->phy->state == OTG_STATE_B_IDLE)
>> +			pm_runtime_put_sync(otg->phy->dev);
>>   		break;
>>   	case OTG_STATE_B_PERIPHERAL:
>>   		dev_dbg(otg->phy->dev, "OTG_STATE_B_PERIPHERAL state\n");
>
> does this need to go on this -rc or can it wait until v3.17 merge

Getting it to rc would be nice :-), but I will leave it up to you.

> window? Also, how far back should this be backported ?

This patch is required if runtime pm is activated.

--srini


>