Hello.
2014-11-03 17:56 GMT+03:00 Lee Jones <lee.jones@xxxxxxxxxx>:
> On Fri, 24 Oct 2014, Dmitry Eremin-Solenikov wrote:
>
>> Some boards with TC6393XB chip require full state restore during system
>> resume thanks to chip's VCC being cut off during suspend (Sharp SL-6000
>> tosa is one of them). Failing to do so would result in ohci Oops on
>> resume due to internal memory contentes being changed. Fail ohci suspend
>> on tc6393xb is full state restore is required.
>>
>> Recommended workaround is to unbind tmio-ohci driver before suspend and
>> rebind it after resume.
>>
>> Signed-off-by: Dmitry Eremin-Solenikov <dbaryshkov@xxxxxxxxx>
>> Cc: stable@xxxxxxxxxxxxxxx
>> ---
>> drivers/mfd/tc6393xb.c | 13 ++++++++++++-
>> 1 file changed, 12 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/mfd/tc6393xb.c b/drivers/mfd/tc6393xb.c
>> index 11c19e5..48579e5 100644
>> --- a/drivers/mfd/tc6393xb.c
>> +++ b/drivers/mfd/tc6393xb.c
>> @@ -263,6 +263,17 @@ static int tc6393xb_ohci_disable(struct platform_device *dev)
>> return 0;
>> }
>>
>> +static int tc6393xb_ohci_suspend(struct platform_device *dev)
>> +{
>> + struct tc6393xb_platform_data *tcpd = dev_get_platdata(dev->dev.parent);
>> +
>> + /* We can't properly store/restore OHCI state, so fail here */
>> + if (tcpd->resume_restore)
>> + return -EBUSY;
>
> Wouldn't it be easier to just put these three lines into
> tc6393xb_ohci_disable() instead off adding 7 superfluous lines and
> making the Ops names inconsistent?
No. The problem only exists on suspend/resume path. tc6393xb_ohci_disable
is also used on driver removal and can (should?) be used on device shutdown.
Using the tc6393xb_ohci_disable() function in that paths is not a problem.
Also with this patch the Oops name will not be inconsistent - returning -EBUSY
from this disable callback will cancel the device suspension with
clearly stating
that OHCI is busy in dmesg.
>
>
>> + return tc6393xb_ohci_disable(dev);
>> +}
>> +
>> static int tc6393xb_fb_enable(struct platform_device *dev)
>> {
>> struct tc6393xb *tc6393xb = dev_get_drvdata(dev->dev.parent);
>> @@ -403,7 +414,7 @@ static struct mfd_cell tc6393xb_cells[] = {
>> .num_resources = ARRAY_SIZE(tc6393xb_ohci_resources),
>> .resources = tc6393xb_ohci_resources,
>> .enable = tc6393xb_ohci_enable,
>> - .suspend = tc6393xb_ohci_disable,
>> + .suspend = tc6393xb_ohci_suspend,
>> .resume = tc6393xb_ohci_enable,
>> .disable = tc6393xb_ohci_disable,
>> },
--
With best wishes
Dmitry
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