| Message ID | 20250124075911.811594-1-badhri@google.com |
|---|---|
| State | New |
| Headers | show |
| Series | [v1] usb: dwc3: gadget: Prevent irq storm when TH re-executes | expand |
diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c index d27af65eb08a..376ab75adc4e 100644 --- a/drivers/usb/dwc3/gadget.c +++ b/drivers/usb/dwc3/gadget.c @@ -4519,7 +4519,7 @@ static irqreturn_t dwc3_check_event_buf(struct dwc3_event_buffer *evt) * losing events. */ if (evt->flags & DWC3_EVENT_PENDING) - return IRQ_HANDLED; + return IRQ_WAKE_THREAD; count = dwc3_readl(dwc->regs, DWC3_GEVNTCOUNT(0)); count &= DWC3_GEVNTCOUNT_MASK;
While commit d325a1de49d6 ("usb: dwc3: gadget: Prevent losing events in event cache") makes sure that top half(TH) does not end up overwriting the cached events before processing them when the TH gets invoked more than one time, returning IRQ_HANDLED results in occasional irq storm where the TH hogs the CPU. The irq storm can be prevented if IRQ_WAKE_THREAD is returned. ftrace event stub during dwc3 irq storm: irq/504_dwc3-1111 ( 1111) [000] .... 70.000866: irq_handler_exit: irq=14 ret=handled irq/504_dwc3-1111 ( 1111) [000] .... 70.000872: irq_handler_entry: irq=504 name=dwc3 irq/504_dwc3-1111 ( 1111) [000] .... 70.000874: irq_handler_exit: irq=504 ret=handled irq/504_dwc3-1111 ( 1111) [000] .... 70.000881: irq_handler_entry: irq=504 name=dwc3 irq/504_dwc3-1111 ( 1111) [000] .... 70.000883: irq_handler_exit: irq=504 ret=handled irq/504_dwc3-1111 ( 1111) [000] .... 70.000889: irq_handler_entry: irq=504 name=dwc3 irq/504_dwc3-1111 ( 1111) [000] .... 70.000892: irq_handler_exit: irq=504 ret=handled irq/504_dwc3-1111 ( 1111) [000] .... 70.000898: irq_handler_entry: irq=504 name=dwc3 irq/504_dwc3-1111 ( 1111) [000] .... 70.000901: irq_handler_exit: irq=504 ret=handled irq/504_dwc3-1111 ( 1111) [000] .... 70.000907: irq_handler_entry: irq=504 name=dwc3 irq/504_dwc3-1111 ( 1111) [000] .... 70.000909: irq_handler_exit: irq=504 ret=handled irq/504_dwc3-1111 ( 1111) [000] .... 70.000915: irq_handler_entry: irq=504 name=dwc3 irq/504_dwc3-1111 ( 1111) [000] .... 70.000918: irq_handler_exit: irq=504 ret=handled irq/504_dwc3-1111 ( 1111) [000] .... 70.000924: irq_handler_entry: irq=504 name=dwc3 irq/504_dwc3-1111 ( 1111) [000] .... 70.000927: irq_handler_exit: irq=504 ret=handled irq/504_dwc3-1111 ( 1111) [000] .... 70.000933: irq_handler_entry: irq=504 name=dwc3 irq/504_dwc3-1111 ( 1111) [000] .... 70.000935: irq_handler_exit: irq=504 ret=handled .... Cc: stable@kernel.org Fixes: d325a1de49d6 ("usb: dwc3: gadget: Prevent losing events in event cache") Signed-off-by: Badhri Jagan Sridharan <badhri@google.com> --- drivers/usb/dwc3/gadget.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) base-commit: 70cd0576aa39c55aabd227851cba0c601e811fb6