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Mon, 09 Nov 2026 18:25:43 -0800 (PST) Received: from google.com ([2a00:79e0:2ebe:8:856b:460b:b522:14ec]) by smtp.gmail.com with ESMTPSA id 5a478bee46e88-3751fe306casm2213095eec.9.2026.11.09.18.25.41 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 09 Nov 2026 18:25:41 -0800 (PST) Date: Mon, 9 Nov 2026 18:25:38 -0800 From: Dmitry Torokhov To: Siarhei Vishniakou Cc: Jiri Kosina , Benjamin Tissoires , Ping Cheng , Jason Gerecke , Jonathan Corbet , Henrik Rydberg , linux-input@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 0/3] Input: add ABS_TWIST and support it in HID and Wacom Message-ID: References: <20261110020632.4003499-1-svv@google.com> X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261110020632.4003499-1-svv@google.com> Hi Siarhei, On Mon, Nov 09, 2026 at 06:06:29PM -0800, Siarhei Vishniakou wrote: > Some styli can report rotation along their long ("barrel") axis, > commonly referred to as "twist". While the HID specification defines > this usage as HID_DG_TWIST (0x000d0041) in the Digitizers page, there is > currently no corresponding evdev axis code to expose it to userspace. > > Because evdev has no MSC_SCAN equivalent for axes, drivers and OEMs > currently work around this by mapping stylus twist onto unrelated axes > such as ABS_Z or ABS_RZ. As a result, userspace input stacks must > maintain device-specific workarounds to know which axis carries twist. How is it different from orientation? Thanks. -- Dmitry