Re: [PATCH v2] usb: dwc2: Fix build in periphal-only mode

[Phil Elwell <phil@raspberrypi.com>]

Hi Greg,

On 28/05/2021 10:23, Greg Kroah-Hartman wrote:
> On Fri, May 28, 2021 at 10:13:50AM +0100, Phil Elwell wrote:
>> The bus_suspended member of struct dwc2_hsotg is only present in builds
>> that support host-mode.
>>
>> Fixes: 24d209dba5a3 ("usb: dwc2: Fix hibernation between host and device modes.")
>> Signed-off-by: Phil Elwell <phil@raspberrypi.com>
>> ---
>>   drivers/usb/dwc2/core_intr.c | 4 ++++
>>   1 file changed, 4 insertions(+)
>>
>> v2: Correct commit hash used in the Fixes line.
>>
>> diff --git a/drivers/usb/dwc2/core_intr.c b/drivers/usb/dwc2/core_intr.c
>> index a5ab03808da6..03d0c034cf57 100644
>> --- a/drivers/usb/dwc2/core_intr.c
>> +++ b/drivers/usb/dwc2/core_intr.c
>> @@ -725,7 +725,11 @@ static inline void dwc_handle_gpwrdn_disc_det(struct dwc2_hsotg *hsotg,
>>   	dwc2_writel(hsotg, gpwrdn_tmp, GPWRDN);
>>   
>>   	hsotg->hibernated = 0;
>> +
>> +#if IS_ENABLED(CONFIG_USB_DWC2_HOST) ||	\
>> +	IS_ENABLED(CONFIG_USB_DWC2_DUAL_ROLE)
>>   	hsotg->bus_suspended = 0;
>> +#endif
>>   
>>   	if (gpwrdn & GPWRDN_IDSTS) {
>>   		hsotg->op_state = OTG_STATE_B_PERIPHERAL;
>> -- 
>> 2.25.1
>>
> 
> I do not understand, the field in the structure is present for all, why
> is this crazy #if needed here?
> 
> I see that the commit you reference here did add the new line to set
> bus_suspended, which seemed to be the point here.  Why will the #if
> values matter here?

Sorry to waste your brain cycles on this. There is a problem, but it only exists 
in branches where the blamed commit (24d209dba5a3) has been back-ported as a 
Fix, because it depends on commit 012466fc8ccc which isn't a Fix and therefore
hasn't been back-ported. Sadly 012466fc8ccc doesn't back-port cleanly on its own 
- either more cherry-picks or a temporary patch like mine will be needed.

Phil