Hi everyone, On Sun, Jul 24, 2022 at 01:48:49PM +0200, José Expósito wrote: > On Fri, 22 Jul 2022, Stefan Hansson wrote: > > Hi! > > > > Somewhere between Linux 5.17.6 and 5.18.11 the Huion tablet I have stopped > > working properly. In GNOME Control Center it is identified as Huion New 1060 > > Plus, however that's a different tablet than the one I have. Mine is a Huion > > Inspiroy H640, and it uses the hid_uclogic driver. > > > > With Linux 5.17.6, the tablet works as expected with all the buttons being > > detected and the stylus being usable. With 5.18.11, the buttons work fine but > > the stylus does not work correctly. The first time I approach the tablet with > > the stylus it works properly, i.e., the cursor on my screen moves around and > > follows the stylus around the tablet as expected. It continues working like > > this until I remove the stylus from the tablet. After I remove it from the > > tablet, the cursor never gets controlled by the stylus again. I can see that > > the tablet detects the stylus (it has a small indicator light), but the cursor > > doesn't move when I approach the tablet again. To clarify, with Linux 5.17.6, > > the cursor moves around just fine when I remove and then put it back to the > > tablet, just as you would expected. > > > > It may also be worth noting that it worked fine when I previously used it > > around six months ago, although I'm not sure what version of Linux I was using > > at that time (whatever Fedora shipped back then). I also tried reproducing it > > with yesterday's linux-next and Linux 5.19.0-RC7, and the behaviour was the > > same as 5.18.11. I am currently trying to bisect this, but it's not going very > > fast as I currently only have access to a dual core laptop from 2014, so > > building Linux takes a good while. > > Thanks a lot for reporting the issue. > > HUION and other non-Wacom tablets are handled by the UCLogic driver. > This driver is present in the kernel but its changes were deployed > and tested first in the DIGImend driver: > https://github.com/DIGImend/digimend-kernel-drivers > > A while ago, I started including in the kernel the code present in > DIGImend. At this moment, 5.19.0-RC7 and DIGImend have the same code > (well, 5.19 has more features, but they don't affect your tablet). > > I'm telling you this because it might be easier for you to bisect the > changes in the DIGImend driver as it builds way faster than the kernel. > Let me know if you need help bisecting it and I'll do my best to help > you. > > Is this your device? > https://www.huion.com/pen_tablet/Inspiroy/H640P.html > > It is affordable, so I ordered it. I don't have any HUION devices to > debug and this is a good excuse to buy one ;) > I'll let you know how it goes once I receive it. The tablet arrived today and it is a bank holiday in Spain, so I had some time to bisect the bug. The first bad commit is 87562fcd1342 ("HID: input: remove the need for HID_QUIRK_INVERT"): https://lore.kernel.org/all/20220203143226.4023622-11-benjamin.tissoires@xxxxxxxxxx/ (CCing the folks whose email is in the patch tags) I reverted the patch on hid/for-next and, after fixing a tiny conflict, I can confirm that the tablet works again as expected. I'd need to investigate a bit more over the weekend, but I think that all HUION tablets with the latest firmware (internally, v2) are affected. Those tablets do not set the inrange bit (UCLOGIC_PARAMS_PEN_INRANGE_NONE). The driver sets it and uses a timer to remove it. See drivers/hid/hid-uclogic-core.c, function uclogic_raw_event_pen(). However, at least the Huion Inspiroy H640, sends a 0x00 byte when the tool is removed, making it possible to fix it in the driver [1]. Unfortunately, the affected code path is used by many tablets and I can not test them, so I'd prefer to hear Benjamin's opinion and see if this should be fixed in hid-input rather than in the driver before sending a fix. Best wishes, José Expósito [1] Diff of a possible fix: diff --git a/drivers/hid/hid-uclogic-core.c b/drivers/hid/hid-uclogic-core.c index 47a17375c7fc..bdcbbd57d0fc 100644 --- a/drivers/hid/hid-uclogic-core.c +++ b/drivers/hid/hid-uclogic-core.c @@ -316,8 +316,11 @@ static int uclogic_raw_event_pen(struct uclogic_drvdata *drvdata, } /* If we need to emulate in-range detection */ if (pen->inrange == UCLOGIC_PARAMS_PEN_INRANGE_NONE) { /* Set in-range bit */ - data[1] |= 0x40; + if (data[1]) + data[1] |= 0x40; + /* (Re-)start in-range timeout */ mod_timer(&drvdata->inrange_timer, jiffies + msecs_to_jiffies(100));
