Re: [PATCH] wifi: rtw88: usb: silence log flooding error message

[Sascha Hauer <s.hauer@pengutronix.de>]

On Wed, May 24, 2023 at 01:34:52PM +0200, Simon Horman wrote:
> On Wed, May 24, 2023 at 12:39:34PM +0200, Sascha Hauer wrote:
> > When receiving more rx packets than the kernel can handle the driver
> > drops the packets and issues an error message. This is bad for two
> > reasons. The logs are flooded with myriads of messages, but then time
> > consumed for printing messages in that critical code path brings down
> > the device. After some time of excessive rx load the driver responds
> > with:
> > 
> > rtw_8822cu 1-1:1.2: failed to get tx report from firmware
> > rtw_8822cu 1-1:1.2: firmware failed to report density after scan
> > rtw_8822cu 1-1:1.2: firmware failed to report density after scan
> > 
> > The device stops working until being replugged.
> > 
> > Fix this by lowering the priority to debug level and also by
> > ratelimiting it.
> > 
> > Fixes: a82dfd33d1237 ("wifi: rtw88: Add common USB chip support")
> > Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
> > ---
> >  drivers/net/wireless/realtek/rtw88/usb.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/drivers/net/wireless/realtek/rtw88/usb.c b/drivers/net/wireless/realtek/rtw88/usb.c
> > index 44a5fafb99055..976eafa739a2d 100644
> > --- a/drivers/net/wireless/realtek/rtw88/usb.c
> > +++ b/drivers/net/wireless/realtek/rtw88/usb.c
> > @@ -535,7 +535,7 @@ static void rtw_usb_rx_handler(struct work_struct *work)
> >  		}
> >  
> >  		if (skb_queue_len(&rtwusb->rx_queue) >= RTW_USB_MAX_RXQ_LEN) {
> > -			rtw_err(rtwdev, "failed to get rx_queue, overflow\n");
> > +			dev_dbg_ratelimited(rtwdev->dev, "failed to get rx_queue, overflow\n");
> 
> This is certainly an improvement. But as I understand things
> it is still somewhat verbose if the condition persists.
> Did you consider dev_dbg_once()?

My rationale was that dev_dbg() is normally disabled anyway. With
CONFIG_DYNAMIC_PRINTK you would still have fine grained control if you
want to see this message or not.

Personally I don't care that much, I would switch to dev_dbg_once() if
that's preferred.

Sascha

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