Hi Alan, > On Tue, Aug 08, 2023 at 06:29:58PM +0800, Xu Yang wrote: > > Some NXP processor using chipidea IP has a bug when frame babble is > > detected. > > > > As per 4.15.1.1.1 Serial Bus Babble: > > A babble condition also exists if IN transaction is in progress at > > High-speed SOF2 point. This is called frame balle. The host controller > > s/balle/babble/ Okay. > > > must disable the port to which the frame babble is detected. > > > > The USB controller has disabled the port (PE cleared) and has asserted > > USBERRINT when frame babble is detected, but PEC is not asserted. > > Therefore, the SW didn't aware that port has been disabled. Then the > > s/didn't/isn't/ Okay. > > > SW keeps sending packets to this port, but all of the transfers will > > fail. > > > > This workaround will firstly assert PCD by SW when USBERRINT is detected > > and then judge whether port change has really occurred or not by polling > > roothub status. Because the PEC doesn't get asserted in our case, this > > patch will also assert it by SW when specific conditions are satisfied. > > > > Signed-off-by: Xu Yang <xu.yang_2@xxxxxxx> > > --- > > drivers/usb/host/ehci-hcd.c | 5 +++++ > > drivers/usb/host/ehci-hub.c | 10 +++++++++- > > drivers/usb/host/ehci.h | 10 ++++++++++ > > 3 files changed, 24 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/usb/host/ehci-hcd.c b/drivers/usb/host/ehci-hcd.c > > index a1930db0da1c..d6b276c354db 100644 > > --- a/drivers/usb/host/ehci-hcd.c > > +++ b/drivers/usb/host/ehci-hcd.c > > @@ -762,6 +762,11 @@ static irqreturn_t ehci_irq (struct usb_hcd *hcd) > > bh = 1; > > } > > > > + /* Force to check port status */ > > + if (ehci->has_ci_pec_bug && (status & STS_ERR) > > + && !(status & STS_PCD)) > > + status |= STS_PCD; > > Suggestion for minor improvement: First, you don't really need the > (status & STS_PCD) test, because if the bit is already set then turning > it again on won't matter. Second, after that test has been removed you > can merge this code with the INCR(ehci->stats.error) line above, > removing the (status & STS_ERR) test. Okay. Will try this. Thanks, Xu Yang > > The rest of the patch looks okay. > > Alan Stern
