> The dev_rdesc member of the hid_device structure is meant to store the original > report descriptor received from the device, but it is currently passed to any > report_fixup method before it is copied to the rdesc member. This patch uses a > temporary buffer to shield dev_rdesc from the side effects of many HID drivers' > report_fixup implementations. > > usbhid's hid_post_reset checks the report descriptor currently returned by the > device against a descriptor that may have been modified by a driver's > report_fixup method. That leaves some devices nonfunctional after a resume, with > a "reset_resume error 1" reported. This patch checks the new descriptor against > the unmodified dev_rdesc instead and uses the original, instead of modified, > report size. > > BugLink: http://bugs.launchpad.net/bugs/1049623 > Signed-off-by: Kevin Daughtridge <kevin@xxxxxxxx> > --- Looks like it will work, thank you Kevin. The comments below are just suggestions, I am fine with the patch as is. > drivers/hid/hid-core.c | 16 +++++++++++++--- > drivers/hid/usbhid/hid-core.c | 6 +++--- > 2 files changed, 16 insertions(+), 6 deletions(-) > > Changed in this version: added a temporary buffer to work around report_fixup > inconsistencies; using dev_rsize instead of rsize to allocate and read new > descriptor. > > diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c > index 8bcd168..5de3bb3 100644 > --- a/drivers/hid/hid-core.c > +++ b/drivers/hid/hid-core.c > @@ -757,6 +757,7 @@ int hid_open_report(struct hid_device *device) > struct hid_item item; > unsigned int size; > __u8 *start; > + __u8 *buf; It is sad to have to add a temporary here. > __u8 *end; > int ret; > static int (*dispatch_type[])(struct hid_parser *parser, > @@ -775,12 +776,21 @@ int hid_open_report(struct hid_device *device) > return -ENODEV; > size = device->dev_rsize; > > + buf = kmemdup(start, size, GFP_KERNEL); > + if (buf == NULL) > + return -ENOMEM; > + > if (device->driver->report_fixup) > - start = device->driver->report_fixup(device, start, &size); > + start = device->driver->report_fixup(device, buf, &size); > + else > + start = buf; > > - device->rdesc = kmemdup(start, size, GFP_KERNEL); > - if (device->rdesc == NULL) > + start = kmemdup(start, size, GFP_KERNEL); > + kfree(buf); Changing the semantics of the callback did not seem appealing, but it does not prevent us from using our own version internally. So, how about something like this: static __u8 *hid_alloc_rdesc(struct hid_device *devicew, const __u8 *start, unsigned int *size) { __u8 *rdesc = kmemdup(start, *size, GFP_KERNEL); if (rdesc && device->driver->report_fixup) { __u8 *tmp = device->driver->report_fixup(device, rdesc, size); if (tmp != rdesc) { tmp = kmemdup(tmp, *size, GFP_KERNEL); kfree(rdesc); rdesc = tmp; } } return rdesc; } > + if (start == NULL) > return -ENOMEM; > + > + device->rdesc = start; > device->rsize = size; > > parser = vzalloc(sizeof(struct hid_parser)); > diff --git a/drivers/hid/usbhid/hid-core.c b/drivers/hid/usbhid/hid-core.c > index dedd8e4..8e0c4bf94 100644 > --- a/drivers/hid/usbhid/hid-core.c > +++ b/drivers/hid/usbhid/hid-core.c > @@ -1415,20 +1415,20 @@ static int hid_post_reset(struct usb_interface *intf) > * configuration descriptors passed, we already know that > * the size of the HID report descriptor has not changed. > */ > - rdesc = kmalloc(hid->rsize, GFP_KERNEL); > + rdesc = kmalloc(hid->dev_rsize, GFP_KERNEL); > if (!rdesc) { > dbg_hid("couldn't allocate rdesc memory (post_reset)\n"); > return 1; > } > status = hid_get_class_descriptor(dev, > interface->desc.bInterfaceNumber, > - HID_DT_REPORT, rdesc, hid->rsize); > + HID_DT_REPORT, rdesc, hid->dev_rsize); > if (status < 0) { > dbg_hid("reading report descriptor failed (post_reset)\n"); > kfree(rdesc); > return 1; > } > - status = memcmp(rdesc, hid->rdesc, hid->rsize); > + status = memcmp(rdesc, hid->dev_rdesc, hid->dev_rsize); > kfree(rdesc); > if (status != 0) { > dbg_hid("report descriptor changed\n"); Thanks, Henrik -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
