[PATCH libdrm 2/3] xf86drm: Add USB support

[Emil Velikov]

Hi Thierry,

On 23 December 2016 at 17:49, Thierry Reding <thierry.reding at gmail.com> wrote:
> Allow DRM/KMS devices hosted on USB to be detected by the drmDevice
> infrastructure.
>
> Signed-off-by: Thierry Reding <thierry.reding at gmail.com>
> ---
> Note that this is completely untested because I don't have a UDL device
> for testing. I'm fairly confident that this will work, though, and it'd
> be nice to include it before the new platform and host1x busses because
> support for it existed in the kernel longer than for platform devices.
>
Functionality looks spot on, but I'm a bit hesitant to get this in
without any testing.
Can we please extend tests/drmdevice.c (separate patch?) as poke
someone on dri-devel/xorg-devel to give it a quick run ?

> +static int drmParseUsbDeviceInfo(int maj, int min, drmUsbDeviceInfoPtr info)
> +{
> +    char path[PATH_MAX + 1], *value;
> +    unsigned int vendor, product;
> +    int ret;
> +
> +    snprintf(path, PATH_MAX, "/sys/dev/char/%d:%d/device", maj, min);
> +
> +    value = sysfs_uevent_get(path, "PRODUCT");
> +    ret = sscanf(value, "%x/%x", &vendor, &product);
> +    free(value);
> +
> +    if (ret <= 0)
> +        return -errno;
> +
> +    info->vendor = vendor;
> +    info->product = product;
> +
Worth fetching bcdDevice as well ?

Thanks
Emil