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libdrm: Handle usb_interface devices for usb parsing 

Currently the code expects that the device found at
/sys/char/$maj:$min/device for USB devices is a "usb_device". However,
at least for some devices, such as for the udl driver, they are instead
a "usb_interface".

A usb_interface is a child of the usb_device we're interested in, so we
walk up one in the /sys path to get there.

For example, with a USB device I have, trimmed to show the relevant
information:
```
$ udevadm info /dev/dri/card1
P: /devices/pci0000:00/0000:00:01.3/0000:02:00.0/usb1/1-4/1-4:1.0/drm/card1
E: DEVTYPE=drm_minor
$ udevadm info /sys/devices/pci0000:00/0000:00:01.3/0000:02:00.0/usb1/1-4/1-4:1.0
E: DEVTYPE=usb_interface
E: DRIVER=udl
$ udevadm info /sys/devices/pci0000:00/0000:00:01.3/0000:02:00.0/usb1/1-4
E: DEVTYPE=usb_device
E: DRIVER=usb
E: BUSNUM=001
E: DEVNUM=009
```

Signed-off-by: Scott Anderson <scott@anderso.nz>
main
Scott Anderson 2020-01-31 16:18:19 +13:00 committed by Emil Velikov
parent 57df07572c
commit bf63f8acdc
1 changed files with 46 additions and 2 deletions
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48
xf86drm.c
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@ -3611,6 +3611,46 @@ free_device:
return ret;
}
#ifdef __linux__
static int drm_usb_dev_path(int maj, int min, char *path, size_t len)
{
char *value, *tmp_path, *slash;
snprintf(path, len, "/sys/dev/char/%d:%d/device", maj, min);
value = sysfs_uevent_get(path, "DEVTYPE");
if (!value)
return -ENOENT;
if (strcmp(value, "usb_device") == 0)
return 0;
if (strcmp(value, "usb_interface") != 0)
return -ENOTSUP;
/* The parent of a usb_interface is a usb_device */
tmp_path = realpath(path, NULL);
if (!tmp_path)
return -errno;
slash = strrchr(tmp_path, '/');
if (!slash) {
free(tmp_path);
return -EINVAL;
}
*slash = '\0';
if (snprintf(path, len, "%s", tmp_path) >= (int)len) {
free(tmp_path);
return -EINVAL;
}
free(tmp_path);
return 0;
}
#endif
static int drmParseUsbBusInfo(int maj, int min, drmUsbBusInfoPtr info)
{
#ifdef __linux__
@ -3618,7 +3658,9 @@ static int drmParseUsbBusInfo(int maj, int min, drmUsbBusInfoPtr info)
unsigned int bus, dev;
int ret;
snprintf(path, sizeof(path), "/sys/dev/char/%d:%d/device", maj, min);
ret = drm_usb_dev_path(maj, min, path, sizeof(path));
if (ret < 0)
return ret;
value = sysfs_uevent_get(path, "BUSNUM");
if (!value)
@ -3657,7 +3699,9 @@ static int drmParseUsbDeviceInfo(int maj, int min, drmUsbDeviceInfoPtr info)
unsigned int vendor, product;
int ret;
snprintf(path, sizeof(path), "/sys/dev/char/%d:%d/device", maj, min);
ret = drm_usb_dev_path(maj, min, path, sizeof(path));
if (ret < 0)
return ret;
value = sysfs_uevent_get(path, "PRODUCT");
if (!value)