BYD automatic protocol detection is extremely unreliable and is often triggers false positives on regular mice, Sentelic touchpads, and other devices. BYD has several documents that have recommended detection sequence, but they conflict with each other and, as far as I can see, still would not produce unique enough output to reliably differentiate BYD from other PS/2 devices. OEMs sourcing BYD devices also do not do us any favors by not supplying any reasonable DMI data and instead leaving turds like "To Be Filled By O.E.M." in place of vendor data, or "System Serial Number" as serial number. On top of that BYD is not truly modern multitouch controller, but rather a single-touch transitional device that only reports absolute coordinates at the beginning of finger contact and then reverts to reporting displacements, and thus not very precise; the only benefit from using BYD mode vs the legacy PS/2 mode is possibility of edge scrolling. Given the above, and the fact that BYD devices are somewhat uncommon, let's disable automatic detection of BYD devices. Users who know they have BYD trackpads or want to experiment can attempt to activate BYD protocol via sysfs: echo -n "byd" > /sys/bus/serio/devices/serio1/drvctl Fixes: https://bugzilla.kernel.org/show_bug.cgi?id=151691 Fixes: https://bugzilla.kernel.org/show_bug.cgi?id=175421 Fixes: https://bugzilla.kernel.org/show_bug.cgi?id=120781 Fixes: https://bugzilla.kernel.org/show_bug.cgi?id=121281 Cc: stable@xxxxxxxxxxxxxxx Signed-off-by: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx> --- drivers/input/mouse/psmouse-base.c | 4 ---- 1 file changed, 4 deletions(-) diff --git a/drivers/input/mouse/psmouse-base.c b/drivers/input/mouse/psmouse-base.c index fb4b185..bee2674 100644 --- a/drivers/input/mouse/psmouse-base.c +++ b/drivers/input/mouse/psmouse-base.c @@ -1115,10 +1115,6 @@ static int psmouse_extensions(struct psmouse *psmouse, if (psmouse_try_protocol(psmouse, PSMOUSE_TOUCHKIT_PS2, &max_proto, set_properties, true)) return PSMOUSE_TOUCHKIT_PS2; - - if (psmouse_try_protocol(psmouse, PSMOUSE_BYD, - &max_proto, set_properties, true)) - return PSMOUSE_BYD; } /* -- 2.8.0.rc3.226.g39d4020 -- Dmitry -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
