From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from relay4-d.mail.gandi.net (relay4-d.mail.gandi.net [217.70.183.196]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E08C6388E66; Wed, 29 Jul 2026 15:02:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.70.183.196 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785337340; cv=none; b=n+ZmZEUQoqDr/N5e/KHkWFFIQZT1C+B/SIk9dHTumhgfguvhcxdwhIaD/zgsH31kPzGT9JQitPyRCGPXOXxAPqZi6n+4LoO2I+2RsPo/PEMiaBkDSkvoKKHcG6IpgmSvugcVVFjmnhxGmEj7s5HA3fkcs/cH6xXQ5/Y4dkHaIMU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785337340; c=relaxed/simple; bh=zK5CNuwfUWl+RkViSkVzxCQa9z/6UOnyRmq6jxbmsZw=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=tQlcg31xIsLhBwaXsmunbYLQayYxDFw84kG/9qN23lNgzt3TQgfLbsGtKYcks18Dk2OHEIRNC1kHTmMitbpDHhigiI/UfvWXX4FCVGYKsaMadGZoXIGnC2QdnMlWlNSNEkKLpUi7yDG5x84h58a/OZtHa1Q9llHOLvbKQwP46zg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=hadess.net; spf=pass smtp.mailfrom=hadess.net; arc=none smtp.client-ip=217.70.183.196 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=hadess.net Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=hadess.net Received: by mail.gandi.net (Postfix) with ESMTPSA id 529B63EDE3; Wed, 29 Jul 2026 15:02:10 +0000 (UTC) Message-ID: <537756340b790add6a3d79939b66f2213fbd6e9e.camel@hadess.net> Subject: Re: [PATCH v5] HID: logitech-hidpp: Add support for HID++ Multi-Platform feature (0x4531) From: Bastien Nocera To: DevExalt , jikos@kernel.org, bentiss@kernel.org Cc: lains@riseup.net, linux-input@vger.kernel.org, linux-kernel@vger.kernel.org, sari.kreitem@exalt.corp-partner.google.com, hbarnor@google.com Date: Wed, 29 Jul 2026 17:02:09 +0200 In-Reply-To: <20260701073727.53636-1-exalt.dev.team@gmail.com> References: <20260625080807.74157-1-exalt.dev.team@gmail.com> <20260701073727.53636-1-exalt.dev.team@gmail.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.60.2 (3.60.2-1.fc44) Precedence: bulk X-Mailing-List: linux-input@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-GND-Sasl: hadess@hadess.net X-GND-State: clean X-GND-Score: 0 X-GND-Cause: 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 Hey, On Wed, 2026-07-01 at 10:37 +0300, DevExalt wrote: > +static DEVICE_ATTR_WO(platform); > + > +static struct attribute *multiplatform_attrs[] =3D { > + &dev_attr_platform.attr, > + NULL > +}; > + > +static const struct attribute_group multiplatform_attribute_group =3D > { > + .attrs =3D multiplatform_attrs, > +}; I just realised that even though you retrieve the list of supported platforms in the code to check whether it's supported, we don't have any ways to read it. It would really be useful if that was fixed before merging, it makes verifying that it works as expected much easier, including whether it can tell user-space that the value changed too. I tested this with a recent K980 Slim Solar+ keyboard, using the info in this PDF to switch between macOS, Windows and Chrome using the keyboard: https://gzhls.at/blob/ldb/e/3/7/1/4d91f22c1050443f6235092b49270fd021e9.pdf Shortcuts to switch between platforms: macos: fn + O windows: fn + P chrome: fn + C The F7 / screenshot key looks like it's something that changes usefully between platforms: - macOS: Shift+Win+4 - Windows: Shift+Win+S - Chrome: SysRq Testing by between all 3 platforms using both the keyboard keys, and the sysfs attribute yielded the same results with the changing key combination generated by the F7 key. Happy to test again when you have read support added to the sysfs attribute. Cheers