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usb: musb: fix MUSB_QUIRK_B_DISCONNECT_99 handling 

In commit 92af4fc6ec ("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: 92af4fc6ec ("usb: musb: Fix suspend with devices connected for a64")
Cc: stable@vger.kernel.org
Tested-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Tested-by: Drew Fustini <drew@beagleboard.org>
Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Link: https://lore.kernel.org/r/20210528140446.278076-1-thomas.petazzoni@bootlin.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Thomas Petazzoni 2021-05-28 16:04:46 +02:00 committed by Greg Kroah-Hartman
parent 03715ea2e3
commit b65ba0c362
1 changed files with 1 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
drivers/usb/musb/musb_core.c
View File

@ -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,