Re: PROBLEM: Regression likely in hid_uclogic driver breaks Huion Inspiroy H640 drawing tablet

On Mon, Aug 22, 2022 at 08:25:52AM +0200, Benjamin Tissoires wrote:

On Sun, Aug 21, 2022 at 1:45 AM Stefan Hansson [off-list ref] wrote:

quoted

quoted

FWIW, I found the issue: the hid-uclogic driver is emitting input data
behind hid-input, and the state between the 2 is desynchronized.

The following patch seems to be working (with the Huion v1 protocol I
have here that I have tweaked to resemble a v2):
---
 From aeedd318e6cb4dbee551f67616302cc7c4308c58 Mon Sep 17 00:00:00 2001
From: Benjamin Tissoires <redacted>
Date: Thu, 18 Aug 2022 15:09:25 +0200
Subject: [PATCH] Fix uclogic

---
  drivers/hid/hid-input.c | 5 ++++-
  1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/hid/hid-input.c b/drivers/hid/hid-input.c
index c6b27aab9041..a3e2397bb3a7 100644
--- a/drivers/hid/hid-input.c
+++ b/drivers/hid/hid-input.c

@@ -1530,7 +1530,10 @@ void hidinput_hid_event(struct hid_device *hid,

struct hid_field *field, struct
               * assume ours
               */
              if (!report->tool)
-                hid_report_set_tool(report, input, usage->code);
+                report->tool = usage->code;
+
+            /* drivers may have changed the value behind our back,
resend it */
+            hid_report_set_tool(report, input, report->tool);
          } else {
              hid_report_release_tool(report, input, usage->code);
          }

What branch should this be applied on top of?

Sorry for that. I had some local commits in my tree that made the
patch unusable. I just formally sent the patch [0] based on the
hid.git/for-next branch which is actually applying on top of v5.19 or
even v5.18.

Cheers,
Benjamin

[0] https://lore.kernel.org/linux-input/20220822062247.1146141-1-benjamin.tissoires@redhat.com/T/#u (local)

As I already commented in the patch, the problem is now solved on
hid/for-next.

Thanks!