usb: msm7k_udc: Add delay upon request dequeue failure
A delay is observed between when the HW generates the
ENDPTCOMPLETE interrupt and updating the dTD status bits. This
delay is causing the request ending up in lying in the DCD queue
which leads to data stall on that particular endpoints.
As temporary workaround add 10 micro second delay upon request
dequeue failure and check for active status bit clear again which
might help this case.
CRs-fixed: 360398
Change-Id: I11e7e224c8eb441315f831d9c6b76f8b410fd963
Signed-off-by: Chiranjeevi Velempati <cvelempa@codeaurora.org>
diff --git a/drivers/usb/gadget/msm72k_udc.c b/drivers/usb/gadget/msm72k_udc.c
index 0921b4f..35ea497 100644
--- a/drivers/usb/gadget/msm72k_udc.c
+++ b/drivers/usb/gadget/msm72k_udc.c
@@ -1109,6 +1109,7 @@
struct msm_endpoint *ept = ui->ept + bit;
struct msm_request *req;
unsigned long flags;
+ int req_dequeue = 1;
unsigned info;
/*
@@ -1128,12 +1129,23 @@
break;
}
+dequeue:
/* clean speculative fetches on req->item->info */
dma_coherent_post_ops();
info = req->item->info;
/* if the transaction is still in-flight, stop here */
- if (info & INFO_ACTIVE)
- break;
+ if (info & INFO_ACTIVE) {
+ if (req_dequeue) {
+ req_dequeue = 0;
+ ui->dTD_update_fail_count++;
+ ept->dTD_update_fail_count++;
+ udelay(10);
+ goto dequeue;
+ } else {
+ break;
+ }
+ }
+ req_dequeue = 0;
del_timer(&ept->prime_timer);
/* advance ept queue to the next request */