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drivers/video/udlfb match class, subclass, and protocol

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Match udlfb only against vendor-specific class (e.g. only DisplayLink
graphics, not composite standard audio class interfaces). This enables
compatibility with composite graphics+audio devices (e.g. HDMI).

Match udlfb only against compatible subclass 0 and protocol 0 chips.
DisplayLink's USB 3.0 generation chips increment these values
to signal that they have a incompatible protocol, preventing udlfb
from erroneously matching to hardware it does not support.

Tested to confirm proper behavior on both USB 2.0 and USB 3.0
generation devices.

Reported-by: Andrew Kephart <akephart@akephart.org>
Signed-off-by: Bernie Thompson <bernie@plugable.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
This commit is contained in:
Bernie Thompson 2011-07-10 00:30:00 -07:00 committed by Paul Mundt
parent c84c14224b
commit b63d10130e
1 changed files with 14 additions and 5 deletions
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19
drivers/video/udlfb.c
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@ -49,13 +49,22 @@ static const u32 udlfb_info_flags = FBINFO_DEFAULT | FBINFO_READS_FAST |
FBINFO_HWACCEL_COPYAREA | FBINFO_MISC_ALWAYS_SETPAR;
/*
* There are many DisplayLink-based products, all with unique PIDs. We are able
* to support all volume ones (circa 2009) with a single driver, so we match
* globally on VID. TODO: Probe() needs to detect when we might be running
* "future" chips, and bail on those, so a compatible driver can match.
* There are many DisplayLink-based graphics products, all with unique PIDs.
* So we match on DisplayLink's VID + Vendor-Defined Interface Class (0xff)
* We also require a match on SubClass (0x00) and Protocol (0x00),
* which is compatible with all known USB 2.0 era graphics chips and firmware,
* but allows DisplayLink to increment those for any future incompatible chips
*/
static struct usb_device_id id_table[] = {
{.idVendor = 0x17e9, .match_flags = USB_DEVICE_ID_MATCH_VENDOR,},
{.idVendor = 0x17e9,
.bInterfaceClass = 0xff,
.bInterfaceSubClass = 0x00,
.bInterfaceProtocol = 0x00,
.match_flags = USB_DEVICE_ID_MATCH_VENDOR |
USB_DEVICE_ID_MATCH_INT_CLASS |
USB_DEVICE_ID_MATCH_INT_SUBCLASS |
USB_DEVICE_ID_MATCH_INT_PROTOCOL,
},
{},
};
MODULE_DEVICE_TABLE(usb, id_table);