Alan Stern wrote:
>On Mon, 13 Mar 2006, Craig W. Nadler wrote:
>
>
>
>> I've put together a patch demonstrating how Interface Association
>>Descriptors could be supported with a minimal amount of changes the
>>current USB stack. When a USB device is enumerated the descriptors are
>>parsed by the code in drivers/usb/core/config.c. A list of IADs for a
>>given configuration would be stored in the usb_host_config struct for
>>that configuration. If an interface is referenced by an IAD then a
>>pointer to the IAD will be stored in the usb_host_interface struct for
>>that interface.
>>
>>
>
>Some minor gammatical comments on the printer gadget patch: "it's" is a
>contraction of "it is", whereas "its" is a possessive pronoun. Also,
>"howto" should be two words ("how to") unless you're using it as a noun.
>
>--- a/drivers/usb/core/config.c 2006-01-02 22:21:10.000000000 -0500
>+++ b/drivers/usb/core/config.c 2006-03-05 01:19:33.000000000 -0500
>@@ -310,6 +312,22 @@
> ++n;
> }
>
>+ } else if (header->bDescriptorType ==
>+ USB_DT_INTERFACE_ASSOCIATION) {
>+ if (iad_num == USB_MAXIADS) {
>+ dev_err(ddev, "found more Interface "
>+ "Association Descriptors "
>+ "than allocated for\n");
>+ } else {
>+ config->intf_assoc[iad_num] = kzalloc(
>+ header->bLength, GFP_KERNEL);
>+ if (!config->intf_assoc[iad_num])
>+ return -ENOMEM;
>+ memcpy (config->intf_assoc[iad_num], header,
>+ header->bLength);
>+ iad_num++;
>+ }
>
>Unless you think that interface association descriptors are critical for
>using the device correctly, you should accept allocation failures and
>continue instead of aborting.
>
>Furthermore, there's no real point in copying the descriptor to this
>newly-allocated memory area. The original data bytes will remain
>available in the raw_descriptors array, so it would be enough to have
>config->intf_assoc[iad_num] be nothing more than a pointer into
>raw_descriptors.
>
>@@ -419,6 +437,10 @@
> struct usb_host_config *cf = &dev->config[c];
>
> kfree(cf->string);
>+ for (i = 0; i < USB_MAXIADS; i++) {
>+ if (cf->intf_assoc[i])
>+ kfree(cf->intf_assoc[i]);
>+ }
>
>The test isn't needed. Of course, if you change intf_assoc[i] to be a
>pointer into raw_descriptors then the kfree and the loop aren't needed
>either.
>
>Alan Stern
>
>
>
>
>
Thank you for pointing that out, I have a new patch that I'm about to
send out.
Best Regards,
Craig Nadler
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