Messages in this thread | | | Subject | Re: Crash caused by hid-rmi and no longer working touchscreen | From | Andrew Duggan <> | Date | Mon, 10 Apr 2017 12:41:38 -0700 |
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On 04/10/2017 11:38 AM, Dmitry Torokhov wrote: > On Mon, Apr 10, 2017 at 03:18:03PM +0200, Jiri Kosina wrote: >> [ a couple more people from "the other regression thread" added to CC ] >> >> On Mon, 10 Apr 2017, Gabriele Mazzotta wrote: >> >>> Hi, >>> >>> I'm having troubles with hid-rmi using 4.11-rc6. I'm getting some >>> "rmi_hid_read_block: timeout elapsed" errors and ultimately the >>> crash you can see at the end of this mail. I will reply to this >>> mail with a full log that shows all the errors. >>> >>> The problem seems to be caused by commit 279967a65b320d174a507498ae >>> ("HID: rmi: Handle all Synaptics touchpads using hid-rmi"). >>> >>> My laptop has a Synaptics touchpad and a Synaptics touchscreen. >>> Because of that commit, hid-rmi is used for both the devices, while >>> it has always been used only for the touchpad. Needless to say that >>> the touchscreen no longer works. >>> >>> If I revert that commit, everything goes back to normal. >> Alright, given this is a second regression cause by this switch, I suggest >> to revert this one for 4.11 still, and work on fixing this properly for >> 4.12. >> >> If noone raises any objections (a few more people added to Cc), I'll queue >> a 4.11-rc revert tomorrow. > Yes, we also have this: > > https://bugzilla.kernel.org/show_bug.cgi?id=195287
I suspect that the issue might be that both of these touchscreens have the HID_GD_POINTER usage defined in their HID report descriptor. This might be because the firmware is configured to support pens. It looks like the Asus T302CA from the bug does have a pen and the XPS13 9333 may simply have firmware which has pen support enabled. The HID_GD_POINTER usage is used in hid-core to differentiate between touchpads and touchscreens. So if a touchscreen has HID_GD_POINTER defined then hid-core will bind hid-rmi to it. None, of my test systems have pen support so I did not anticipate this.
Also, the reason why we can't just support touchscreens using hid-rmi is because the firmware for HID touchscreens lacks the functionality of reporting the attention data (finger positions) in a single report. It ends up being less efficient to run HID touchscreens in RMI mode.
> so reverting seems prudent at this time.
Yes, I agree we should revert the commit. There simply isn't enough time to come up with and test a new method for differentiating touchpads and touchscreens before 4.11 is released.
Andrew
> Thanks. >
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