[PATCH] usb: dwc3: gadget: Fix failure to detect end of transfer

[PATCH] usb: dwc3: gadget: Fix failure to detect end of transfer

[Bryan O'Donoghue]

A recent bugfix 8c7d4b7b3d43 ("usb: dwc3: gadget: Fix logical condition")
correctly fixes a logical error in the gadget driver but, exposes a further
bug in determining when a transfer has completed.

Prior to 8c7d4b7b3d43 we were calling dwc3_gadget_giveback() when we
shouldn't have been. Afer this change the below test fails to complete on
my hardware.

Host:
echo "host" > /dev/ttyACM0

Device:
cat < /dev/ttyGS0

This is caused by the driver incorrectly detecting end of transfer, a
problem that had previous been masked by the continuous calling of
dwc3_gadget_giveback() prior to 8c7d4b7b3d43.

Remediate by making the test <= instead of ==

Fixes: e0c42ce590fe ("usb: dwc3: gadget: simplify IOC handling")

Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
---
 drivers/usb/dwc3/gadget.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 0c960a97ea02..464c4d9961c7 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -2467,7 +2467,7 @@ static int dwc3_gadget_ep_reclaim_trb_linear(struct dwc3_ep *dep,
 
 static bool dwc3_gadget_ep_request_completed(struct dwc3_request *req)
 {
-	return req->request.actual == req->request.length;
+	return req->request.actual <= req->request.length;
 }
 
 static int dwc3_gadget_ep_cleanup_completed_request(struct dwc3_ep *dep,
-- 
2.24.0

Re: [PATCH] usb: dwc3: gadget: Fix failure to detect end of transfer

[Greg KH]

On Mon, Dec 30, 2019 at 04:13:21PM +0000, Bryan O'Donoghue wrote:
> A recent bugfix 8c7d4b7b3d43 ("usb: dwc3: gadget: Fix logical condition")
> correctly fixes a logical error in the gadget driver but, exposes a further
> bug in determining when a transfer has completed.
> 
> Prior to 8c7d4b7b3d43 we were calling dwc3_gadget_giveback() when we
> shouldn't have been. Afer this change the below test fails to complete on
> my hardware.
> 
> Host:
> echo "host" > /dev/ttyACM0
> 
> Device:
> cat < /dev/ttyGS0
> 
> This is caused by the driver incorrectly detecting end of transfer, a
> problem that had previous been masked by the continuous calling of
> dwc3_gadget_giveback() prior to 8c7d4b7b3d43.
> 
> Remediate by making the test <= instead of ==
> 
> Fixes: e0c42ce590fe ("usb: dwc3: gadget: simplify IOC handling")
> 
> Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
> ---
>  drivers/usb/dwc3/gadget.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

I think this patch:
	https://lore.kernel.org/linux-usb/ac5a3593a94fdaa3d92e6352356b5f7a01ccdc7c.1576291140.git.thinhn@synopsys.com/

should fix this issue instead, right?

If not, do I need to include both of these?

thanks,

greg k-h

Re: [PATCH] usb: dwc3: gadget: Fix failure to detect end of transfer

[Bryan O'Donoghue]

On 30/12/2019 18:57, Greg KH wrote:
> On Mon, Dec 30, 2019 at 04:13:21PM +0000, Bryan O'Donoghue wrote:
>> A recent bugfix 8c7d4b7b3d43 ("usb: dwc3: gadget: Fix logical condition")
>> correctly fixes a logical error in the gadget driver but, exposes a further
>> bug in determining when a transfer has completed.
>>
>> Prior to 8c7d4b7b3d43 we were calling dwc3_gadget_giveback() when we
>> shouldn't have been. Afer this change the below test fails to complete on
>> my hardware.
>>
>> Host:
>> echo "host" > /dev/ttyACM0
>>
>> Device:
>> cat < /dev/ttyGS0
>>
>> This is caused by the driver incorrectly detecting end of transfer, a
>> problem that had previous been masked by the continuous calling of
>> dwc3_gadget_giveback() prior to 8c7d4b7b3d43.
>>
>> Remediate by making the test <= instead of ==
>>
>> Fixes: e0c42ce590fe ("usb: dwc3: gadget: simplify IOC handling")
>>
>> Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
>> ---
>>   drivers/usb/dwc3/gadget.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> I think this patch:
> 	https://lore.kernel.org/linux-usb/ac5a3593a94fdaa3d92e6352356b5f7a01ccdc7c.1576291140.git.thinhn@synopsys.com/
> 
> should fix this issue instead, right?
> 
> If not, do I need to include both of these?

Yep, works fine in isolation.

Re: [PATCH] usb: dwc3: gadget: Fix failure to detect end of transfer

[Bryan O'Donoghue]

On 31/12/2019 00:05, Bryan O'Donoghue wrote:
> On 30/12/2019 18:57, Greg KH wrote:
>> On Mon, Dec 30, 2019 at 04:13:21PM +0000, Bryan O'Donoghue wrote:
>>> A recent bugfix 8c7d4b7b3d43 ("usb: dwc3: gadget: Fix logical 
>>> condition")
>>> correctly fixes a logical error in the gadget driver but, exposes a 
>>> further
>>> bug in determining when a transfer has completed.
>>>
>>> Prior to 8c7d4b7b3d43 we were calling dwc3_gadget_giveback() when we
>>> shouldn't have been. Afer this change the below test fails to 
>>> complete on
>>> my hardware.
>>>
>>> Host:
>>> echo "host" > /dev/ttyACM0
>>>
>>> Device:
>>> cat < /dev/ttyGS0
>>>
>>> This is caused by the driver incorrectly detecting end of transfer, a
>>> problem that had previous been masked by the continuous calling of
>>> dwc3_gadget_giveback() prior to 8c7d4b7b3d43.
>>>
>>> Remediate by making the test <= instead of ==
>>>
>>> Fixes: e0c42ce590fe ("usb: dwc3: gadget: simplify IOC handling")
>>>
>>> Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
>>> ---
>>>   drivers/usb/dwc3/gadget.c | 2 +-
>>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> I think this patch:
>>     https://lore.kernel.org/linux-usb/ac5a3593a94fdaa3d92e6352356b5f7a01ccdc7c.1576291140.git.thinhn@synopsys.com/ 
>>
>>
>> should fix this issue instead, right?
>>
>> If not, do I need to include both of these?
> 
> Yep, works fine in isolation.
> 

I don't have that in my inbox anywhere - not sure why, would have saved 
me 1/2 a day of work.

Anyway, please feel free to add my

Tested-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org> to Thinh's patch

---
bod