| Message ID | 20210528140446.278076-1-thomas.petazzoni@bootlin.com |
|---|---|
| State | Accepted |
| Commit | b65ba0c362be665192381cc59e3ac3ef6f0dd1e1 |
| Headers | show |
| Series | usb: musb: fix MUSB_QUIRK_B_DISCONNECT_99 handling | expand |
On 28/05/2021 16:04:46+0200, Thomas Petazzoni wrote: > In commit 92af4fc6ec33 ("usb: musb: Fix suspend with devices > connected for a64"), the logic to support the > MUSB_QUIRK_B_DISCONNECT_99 quirk was modified to only conditionally > schedule the musb->irq_work delayed work. > > This commit badly breaks ECM Gadget on AM335X. Indeed, with this > commit, one can observe massive packet loss: > > $ ping 192.168.0.100 > ... > 15 packets transmitted, 3 received, 80% packet loss, time 14316ms > > Reverting this commit brings back a properly functioning ECM > Gadget. An analysis of the commit seems to indicate that a mistake was > made: the previous code was not falling through into the > MUSB_QUIRK_B_INVALID_VBUS_91, but now it is, unless the condition is > taken. > > Changing the logic to be as it was before the problematic commit *and* > only conditionally scheduling musb->irq_work resolves the regression: > > $ ping 192.168.0.100 > ... > 64 packets transmitted, 64 received, 0% packet loss, time 64475ms > > Fixes: 92af4fc6ec33 ("usb: musb: Fix suspend with devices connected for a64") > Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com> Tested-by: Alexandre Belloni <alexandre.belloni@bootlin.com> > Cc: stable@vger.kernel.org > --- > drivers/usb/musb/musb_core.c | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) > > diff --git a/drivers/usb/musb/musb_core.c b/drivers/usb/musb/musb_core.c > index 8f09a387b773..4c8f0112481f 100644 > --- a/drivers/usb/musb/musb_core.c > +++ b/drivers/usb/musb/musb_core.c > @@ -2009,9 +2009,8 @@ static void musb_pm_runtime_check_session(struct musb *musb) > schedule_delayed_work(&musb->irq_work, > msecs_to_jiffies(1000)); > musb->quirk_retries--; > - break; > } > - fallthrough; > + break; > case MUSB_QUIRK_B_INVALID_VBUS_91: > if (musb->quirk_retries && !musb->flush_irq_work) { > musb_dbg(musb, > -- > 2.31.1 >
diff --git a/drivers/usb/musb/musb_core.c b/drivers/usb/musb/musb_core.c index 8f09a387b773..4c8f0112481f 100644 --- a/drivers/usb/musb/musb_core.c +++ b/drivers/usb/musb/musb_core.c @@ -2009,9 +2009,8 @@ static void musb_pm_runtime_check_session(struct musb *musb) schedule_delayed_work(&musb->irq_work, msecs_to_jiffies(1000)); musb->quirk_retries--; - break; } - fallthrough; + break; case MUSB_QUIRK_B_INVALID_VBUS_91: if (musb->quirk_retries && !musb->flush_irq_work) { musb_dbg(musb,
In commit 92af4fc6ec33 ("usb: musb: Fix suspend with devices connected for a64"), the logic to support the MUSB_QUIRK_B_DISCONNECT_99 quirk was modified to only conditionally schedule the musb->irq_work delayed work. This commit badly breaks ECM Gadget on AM335X. Indeed, with this commit, one can observe massive packet loss: $ ping 192.168.0.100 ... 15 packets transmitted, 3 received, 80% packet loss, time 14316ms Reverting this commit brings back a properly functioning ECM Gadget. An analysis of the commit seems to indicate that a mistake was made: the previous code was not falling through into the MUSB_QUIRK_B_INVALID_VBUS_91, but now it is, unless the condition is taken. Changing the logic to be as it was before the problematic commit *and* only conditionally scheduling musb->irq_work resolves the regression: $ ping 192.168.0.100 ... 64 packets transmitted, 64 received, 0% packet loss, time 64475ms Fixes: 92af4fc6ec33 ("usb: musb: Fix suspend with devices connected for a64") Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com> Cc: stable@vger.kernel.org --- drivers/usb/musb/musb_core.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)