On Tue, 09 Apr 2024 16:56:53 +0200, Alan Stern wrote: > > On Tue, Apr 09, 2024 at 03:49:01PM +0200, Oliver Neukum wrote: > > Hi, > > > > with the following device: > > > > Bus 002 Device 002: ID fb5d:0001 BHYVE HID Tablet > > Device Descriptor: > > bLength 18 > > bDescriptorType 1 > > bcdUSB 3.00 > > bDeviceClass 0 > > bDeviceSubClass 0 > > bDeviceProtocol 0 > > bMaxPacketSize0 8 > > A USB-3 device, running at SuperSpeed with its bMaxPacketSize0 set to 8 > instead of 9? Presumably this thing never received a USB certification. > Does the packaging use the USB logo? IIUC from the report, this is a virtualization environment, no real device: https://bhyve.npulse.net/ Takashi > > idVendor 0xfb5d > > idProduct 0x0001 > > bcdDevice 0.00 > > iManufacturer 1 BHYVE > > iProduct 2 HID Tablet > > iSerial 3 01 > > bNumConfigurations 1 > > Why on earth would an HID tablet need to run at SuperSpeed? > > > Binary Object Store Descriptor: > > bLength 5 > > bDescriptorType 15 > > wTotalLength 0x000f > > bNumDeviceCaps 1 > > SuperSpeed USB Device Capability: > > bLength 10 > > bDescriptorType 16 > > bDevCapabilityType 3 > > bmAttributes 0x00 > > wSpeedsSupported 0x0008 > > Device can operate at SuperSpeed (5Gbps) > > bFunctionalitySupport 3 > > Lowest fully-functional device speed is SuperSpeed (5Gbps) > > bU1DevExitLat 10 micro seconds > > bU2DevExitLat 32 micro seconds > > A tablet not capable of running at any speed below 5 Gbps? > > > we are getting a regression on enumeration. It used to work with the > > code prior to your patch. Takashi is proposing the attached fixed. > > It looks like we are a bit too restrictive and should just try. > > > > Regards > > Oliver > > > From: Takashi Iwai <tiwai@xxxxxxx> > > Subject: [PATCH] USB: hub: Workaround for buggy max packet size with super > > speed > > Patch-mainline: Not yet, testing > > References: bsc#1220569 > > > > Signed-off-by: Takashi Iwai <tiwai@xxxxxxx> > > > > --- > > drivers/usb/core/hub.c | 13 ++++++++++--- > > 1 file changed, 10 insertions(+), 3 deletions(-) > > > > diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c > > index e38a4124f610..64193effc456 100644 > > --- a/drivers/usb/core/hub.c > > +++ b/drivers/usb/core/hub.c > > @@ -4830,7 +4830,7 @@ hub_port_init(struct usb_hub *hub, struct usb_device *udev, int port1, > > const char *driver_name; > > bool do_new_scheme; > > const bool initial = !dev_descr; > > - int maxp0; > > + int maxp0, ep0_maxp; > > struct usb_device_descriptor *buf, *descr; > > > > buf = kmalloc(GET_DESCRIPTOR_BUFSIZE, GFP_NOIO); > > @@ -5070,7 +5070,8 @@ hub_port_init(struct usb_hub *hub, struct usb_device *udev, int port1, > > else > > i = 0; /* Invalid */ > > } > > - if (usb_endpoint_maxp(&udev->ep0.desc) == i) { > > + ep0_maxp = usb_endpoint_maxp(&udev->ep0.desc); > > + if (ep0_maxp == i) { > > This variable looks like it was left over from earlier testing. It's > not really needed. > > > ; /* Initial ep0 maxpacket guess is right */ > > } else if ((udev->speed == USB_SPEED_FULL || > > udev->speed == USB_SPEED_HIGH) && > > @@ -5082,9 +5083,15 @@ hub_port_init(struct usb_hub *hub, struct usb_device *udev, int port1, > > dev_warn(&udev->dev, "Using ep0 maxpacket: %d\n", i); > > udev->ep0.desc.wMaxPacketSize = cpu_to_le16(i); > > usb_ep0_reinit(udev); > > + } else if (udev->speed >= USB_SPEED_SUPER && initial) { > > + /* FIXME: should be more restrictive? */ > > + /* Initial guess is wrong; use the descriptor's value */ > > + dev_warn(&udev->dev, "Using ep0 maxpacket: %d\n", i); > > + udev->ep0.desc.wMaxPacketSize = cpu_to_le16(i); > > + usb_ep0_reinit(udev); > > This could be merged with the previous case fairly easily. > > > } else { > > /* Initial guess is wrong and descriptor's value is invalid */ > > - dev_err(&udev->dev, "Invalid ep0 maxpacket: %d\n", maxp0); > > + dev_err(&udev->dev, "Invalid ep0 maxpacket: %d, expected %d\n", maxp0, ep0_maxp); > > This also looks like a remnant from earlier testing. > > Alan Stern > > > retval = -EMSGSIZE; > > goto fail; > > } > > -- > > 2.35.3 > > >
