From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-4322.protonmail.ch (mail-4322.protonmail.ch [185.70.43.22]) (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 9149624EAB1 for ; Wed, 20 Aug 2025 04:47:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.70.43.22 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755665230; cv=none; b=TQwIHe+kZcGDmhg1hZBbXLdwARoZtdnfvDhpBBOt5LnHgdOsdSgWFj5ZT621B3ut+KoqH1NabZXeitey5iVvGa6WEAQdE/eWlWjS1pdLvdDay4bmSqGijALJQFHTUsbN8vyRI2TZtKorfrjoO9Sq5uhvz2gTKgSkXmMgHuuxFBk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755665230; c=relaxed/simple; bh=H+hmRhOUdJIQOWA7MoeeChMlCXqd6iW6mSUpm6KLTgQ=; h=Date:To:From:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=Ckxft0/VjUtqyG9UkfnY1J1vEAtRgedXDFM9+v9TK3a2MCnU7R3O/iPZCahNEyTWeA5W5iRn7fMsaVbYUDgUv3KHSh6tpwwuzANRglh8g1mBaiPouCOc9d+ZyTjR2OcOvaWRorwAoVn9bBBY4tY0AgyXDR2SXbKWrusAJxZn7aI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=protonmail.com; spf=pass smtp.mailfrom=protonmail.com; dkim=pass (2048-bit key) header.d=protonmail.com header.i=@protonmail.com header.b=ghhsMMsE; arc=none smtp.client-ip=185.70.43.22 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=protonmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=protonmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=protonmail.com header.i=@protonmail.com header.b="ghhsMMsE" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=protonmail.com; s=protonmail3; t=1755665220; x=1755924420; bh=H+hmRhOUdJIQOWA7MoeeChMlCXqd6iW6mSUpm6KLTgQ=; h=Date:To:From:Cc:Subject:Message-ID:In-Reply-To:References: Feedback-ID:From:To:Cc:Date:Subject:Reply-To:Feedback-ID: Message-ID:BIMI-Selector; b=ghhsMMsEHXcAb3uyp42Pbxl9JVZroFgWo41jFN7GDwntqO8xABhbef2KB9cnPGcUy DvXBCpGo58s1PN3Ikh8q7Dd37DyrIrL4S/7Gtw7JTA7bJoGO3aAvlhe4w6eh0s4xmJ Vab7iertxyz2giusvQ1+JECSy4/+GEf8LRY+deyNY2oDLLBhTmzi8qP2HiDcBN9yFV nE+zbz+495Ct9jdt5IHuHtcv1LqZOJqNU2qcvpwKsWUENpEgjxPv3EQvZe/jdFNr8x Nf2UcMTdUzdKLYRbjVry7ju6wyOSHvYOeJq7ofNcM+UydMG3lAVFAVtJi3E+9SasLp I0PW7ipkINngw== Date: Wed, 20 Aug 2025 04:46:52 +0000 To: Maxime Ripard From: Rahul Rameshbabu Cc: rust-for-linux@vger.kernel.org, dri-devel@lists.freedesktop.org, Maarten Lankhorst , Thomas Zimmermann , David Airlie , Simona Vetter , Miguel Ojeda , Alex Gaynor , Boqun Feng , Gary Guo , =?utf-8?Q?Bj=C3=B6rn_Roy_Baron?= , Benno Lossin , Andreas Hindborg , Alice Ryhl , Trevor Gross , Danilo Krummrich Subject: Re: [RFC PATCH 0/3] Initial plumbing for implementing DRM connector APIs in Rust Message-ID: <87ect61txs.fsf@protonmail.com> In-Reply-To: References: <20250818050251.102399-2-sergeantsagara@protonmail.com> Feedback-ID: 26003777:user:proton X-Pm-Message-ID: c998b452f60dab47f9847f3197f5c57c7e8ddba8 Precedence: bulk X-Mailing-List: rust-for-linux@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable On Tue, 19 Aug, 2025 11:06:40 +0200 "Maxime Ripard" wr= ote: > Hi Rahul, > > On Mon, Aug 18, 2025 at 05:04:15AM +0000, Rahul Rameshbabu wrote: >> I am working on a drm_connector scoped backlight API in Rust. I have bee= n >> looking through Hans de Goede's previous efforts on this topic to help >> guide my design. My hope is to enable backlight control over external >> displays through DDC or USB Monitor Control Class while also supporting >> internal panels. In parallel, I would like to improve the driver >> probing/selection mechanism when there are different candidates for driv= ing >> a backlight device. This initial RFC is mainly intended to sanity check >> that the plumbing I have chosen for extending the DRM connector >> functionality in Rust seems reasonable. > > It's a great goal, and I had that same discussion with Hans recently > too, but I can't find the link between backling/DDC CI, and Rust. Can > you elaborate? Hi Maxime, Sure, let me elaborate on this. You are right that plumbing DDC CI/backlight support at the DRM connector level does not need to be implemented in Rust. If we look at Hans's proposal, the suggested phase 2 was to add a drm_connector helper function for plumbing a pointer to the backlight device implementation. I had some model differences with regards to how the API would look like, mostly stemming from concerns about providing better runtime overriding of the acpi_video_get_backlight_type based backlight selection. However, I am aligned with the direction of scoping at the drm_connector level. I basically was interested in implementing this helper functionality in Rust instead of C, which is where Rust came into play. I was also interested in declaring and attaching a drm_property in Rust for controlling properties such as backlight rather than updating the drm_connector declaration in C as an experiment. Let me know if you feel like this work would be better off as a C implementation. I can also send out a detailed architecture proposal to the mailing list if that would help. Link: https://lore.freedesktop.org/wayland-devel/0d188965-d809-81b5-74ce-7d= 30c49fee2d@redhat.com/ Thanks, Rahul Rameshbabu > > Maxime