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HID: keep dev_rdesc unmodified and use it for comparisons 

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@kdau.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
hifive-unleashed-5.1
Kevin Daughtridge 2012-09-20 12:00:32 -07:00 committed by Jiri Kosina
parent 4cc9834518
commit 86e6b77eb7
2 changed files with 18 additions and 8 deletions
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20
drivers/hid/hid-core.c
View File

@ -757,6 +757,7 @@ int hid_open_report(struct hid_device *device)
struct hid_item item;
unsigned int size;
__u8 *start;
__u8 *buf;
__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;
if (device->driver->report_fixup)
start = device->driver->report_fixup(device, start, &size);
device->rdesc = kmemdup(start, size, GFP_KERNEL);
if (device->rdesc == NULL)
buf = kmemdup(start, size, GFP_KERNEL);
if (buf == NULL)
return -ENOMEM;
if (device->driver->report_fixup)
start = device->driver->report_fixup(device, buf, &size);
else
start = buf;
start = kmemdup(start, size, GFP_KERNEL);
kfree(buf);
if (start == NULL)
return -ENOMEM;
device->rdesc = start;
device->rsize = size;
parser = vzalloc(sizeof(struct hid_parser));

6
drivers/hid/usbhid/hid-core.c
View File

@ -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");