Re: [PATCH] fsl_usb2_udc: Add a wmb before priming endpoint.

From: Will Newton
Date: Thu Jun 05 2008 - 08:00:32 EST


On Tue, Jun 3, 2008 at 6:24 PM, Felipe Balbi <me@xxxxxxxxxxxxxxx> wrote:
> On Tue, Jun 03, 2008 at 04:20:25PM +0100, Will Newton wrote:
>> Add a wmb to fsl_queue_td before priming the endpoint. This ensures that the
>> modifications to the QH are seen by the hardware.
>>
>> Signed-off-by: Will Newton <will.newton@xxxxxxxxx>
>> ---
>> drivers/usb/gadget/fsl_usb2_udc.c | 2 ++
>> 1 files changed, 2 insertions(+), 0 deletions(-)
>>
>> diff --git a/drivers/usb/gadget/fsl_usb2_udc.c
>> b/drivers/usb/gadget/fsl_usb2_udc.c
>> index 1868754..dd06a5b 100644
>> --- a/drivers/usb/gadget/fsl_usb2_udc.c
>> +++ b/drivers/usb/gadget/fsl_usb2_udc.c
>> @@ -653,6 +653,8 @@ static int fsl_queue_td(struct fsl_ep *ep, struct
>> fsl_req *req)
>> | EP_QUEUE_HEAD_STATUS_HALT));
>> dQH->size_ioc_int_sts &= temp;
>>
>> + wmb();
>
> checkpatch.pl will complain that there's not comment above the memory
> barrier. Could you just add it and in one line summarize why wmb()??

Yes, I'll do that and resend the patch along with the rest of the series I have.

My checkpatch does not seem to complain about the missing comment btw.
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