On Thursday 13 January 2005 10:04 am, Alan Stern wrote:
>
> Okay, here's a patch that looks pretty good to me. The only thing I'm not
> sure about is that it may retry _too_ aggressively. If you like it I'll
> submit it to Greg.
Looks OK to me too, except that if all the first three tries fail it
still goes ahead and uses a bogus ep0 maxpacket size. (Maybe it should
just go right to the other scheme?)
Also, the changelog should highlight the switch to a more accommodating
scheme for enumeration. (Probably worth doing that in a separate patch.)
- Dave
> Alan Stern
>
>
> ===== drivers/usb/core/hub.c 1.223 vs edited =====
> --- 1.223/drivers/usb/core/hub.c 2005-01-11 12:14:56 -05:00
> +++ edited/drivers/usb/core/hub.c 2005-01-13 11:51:32 -05:00
> @@ -75,7 +75,7 @@
> MODULE_PARM_DESC(old_scheme_first,
> "start with the old device initialization scheme");
>
> -static int use_both_schemes = 0;
> +static int use_both_schemes = 1;
> module_param(use_both_schemes, bool, S_IRUGO | S_IWUSR);
> MODULE_PARM_DESC(use_both_schemes,
> "try the other device initialization scheme if the "
> @@ -2180,24 +2180,35 @@
> retval = -ENOMEM;
> continue;
> }
> - buf->bMaxPacketSize0 = 0;
>
> /* Use a short timeout the first time through,
> * so that recalcitrant full-speed devices with
> * 8- or 16-byte ep0-maxpackets won't slow things
> * down tremendously by NAKing the unexpectedly
> - * early status stage. Also, retry on length 0
> - * or stall; some devices are flakey.
> + * early status stage. Also, retry on all errors;
> + * some devices are flakey.
> */
> for (j = 0; j < 3; ++j) {
> + buf->bMaxPacketSize0 = 0;
> r = usb_control_msg(udev, usb_rcvaddr0pipe(),
> USB_REQ_GET_DESCRIPTOR, USB_DIR_IN,
> USB_DT_DEVICE << 8, 0,
> buf, GET_DESCRIPTOR_BUFSIZE,
> (i ? HZ * USB_CTRL_GET_TIMEOUT : HZ));
> - if (r == 0 || r == -EPIPE)
> - continue;
> - if (r < 0)
> + switch (buf->bMaxPacketSize0) {
> + case 8: case 16: case 32: case 64:
> + if (buf->bDescriptorType ==
> + USB_DT_DEVICE) {
> + r = 0;
> + break;
> + }
> + /* FALL THROUGH */
> + default:
> + if (r == 0)
> + r = -EPROTO;
> + break;
> + }
> + if (r == 0)
> break;
> }
> udev->descriptor.bMaxPacketSize0 =
> @@ -2213,10 +2224,7 @@
> retval = -ENODEV;
> goto fail;
> }
> - switch (udev->descriptor.bMaxPacketSize0) {
> - case 64: case 32: case 16: case 8:
> - break;
> - default:
> + if (r) {
> dev_err(&udev->dev, "device descriptor "
> "read/%s, error %d\n",
> "64", r);
>
>
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