On 2022-09-26 01:52:37 +0200, Marek Vasut wrote:

On 8/29/22 08:31, Janne Grunau wrote:

...

Fixes probing of various keyboards with DWC3 as integrated into Apple silicon SoCs. The problem appears to be requesting more data than the devices's bMaxPacketSize0 of 8. Older Logitech unifying receivers (bcdDevice 12.03 or 12.10) are for eaxample affected.

Signed-off-by: Janne Grunau j@jannau.net Tested-by: Thomas Glanzmann thomas@glanzmann.de

---

common/usb.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/common/usb.c b/common/usb.c index 6fcf1e8428e9..48a310e8599d 100644 --- a/common/usb.c +++ b/common/usb.c @@ -993,10 +993,12 @@ static int usb_setup_descriptor(struct usb_device *dev, bool do_read) * * At least the DWC2 controller needs to be programmed with * the number of packets in addition to the number of bytes.

•  * A request for 64 bytes of data with the maxpacket guessed
  

•  * as 64 (above) yields a request for 1 packet.
  

•  * Requesting more than 8 bytes causes probing errors on the
  

•  * DWC3 controller integrated into Apple silicon SoCs with
  

•  * devices with bMaxPacketSize0 of 8. So limit the read request
  

•  * to the used size of 8 bytes.
  

  */

• err = get_descriptor_len(dev, 64, 8);
  

• err = get_descriptor_len(dev, 8, 8);
  

  if (err) return err; }

Sorry for the delay.

Can you be more specific about those logitech receivers ?

In my case it's a device a little bit larger than a USB-A plug. ~7mm heigh black plastic case with "logitech" written on the end and and their unifying logo in orange on a side (idVendor: 0x046d, idProduct: 0xc52b, bcdDevice: 12.03). Russell has one with bcdDevice: 12.10

The problem is not limited to the logitech receivers. It reproduces for other keyboards with bMaxPacketSize0 == 8 as well. I suspect it affects all devices with bMaxPacketSize0 == 8. Keyboards are simply the type of device those breakage is noticed inside u-boot / efi bootloaders on desktop class devices and don't transfer that much data so that bMaxPacketSize0 == 8 doesn't hurt.

I might have one of those devices, and I have DWC3 in i.MX8MP and i.MX8MQ, as well as ZynqMP, so I should be able to try and trigger the problem. Can you share the reproducer test case for this problem ?

The device is not detected. It is not listed as detected usb device during u-boot's USB probing. If the device is a keyboard or you have a matching logitech wireless keyboard it will not work to interrupt the auto boot or on the u-boot prompt.

If the problem is specific to the Apple instance of the controller, maybe we need some sort of quirk instead ?

The code looks evidently broken to me. The comment says that we can only expect to receive a single packet. We request 64 bytes but devices might have a bMaxPacketSize0 of 8. Requesting more than 8 bytes looks also unnecessary as we are only interested in bMaxPacketSize0 which is within the first 8 bytes of the device descriptor.

Thanks

Janne