From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=148.251.105.195 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793991959; b=jLWmqzyTLTZ2Ncb8+qqTL3MMKGPEVKB3y4+rVrvRI5/1fj2U/NJyoAS/pGQUhREDQLQw z4S/8Sb/CZ0HOV+rZvPrXhx8rgRG2+WGvp+7tBJFSCvUJYoh/MrEjAQxfPClLnRl2iTfS 6VvgsvnwU/AqG72dRoThjvLo9jV93SGLq6nIT+K3LpDeCoxkpljo+g8kWKipXSsfPJTbo 1NrkBKu+DUDs49c3A0BBE3zMothAcJOEysYaApP3CxgvB1FcVcCdyr9rpXXqr4T2xO6bY kD4AlKYfgcZ+ezpLR1N1ZeOHQo9XqxW2xAzHFt5SIz1UojgjBcZA779dJ4vdxxzo7eA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793991959; h=DMARC-Filter:DKIM-Signature:Received:Message-ID:Subject:From:To:Cc: Date:In-Reply-To:References:Autocrypt:Organization:Content-Type: User-Agent:MIME-Version; bh=6LdXT14KOb6OCBtyF62RqXz9icJXVGvFn0shQuZytOU=; b=NAvLHghpuX34Qk1OYb3gqxxV87GbhNiYh++MHRoUQVKUo/BTzCGsv0z8GrI0oL9jQJBR OFpJIqhc3lSsdbmfNfa9ITWQZAs4zWs163OejcZ1r4uAVx0HAe3ZQVUE2qYRC2AK89aQr ZLdWrc3/G5nr9bPYerVp+FeeQn4f5LPHm+CGJFuCf8kcJMEO66VOrZtukbCnJjpIa7rOG 5CDHCZ0OO6UwS2x4AK6VN9kcQdx/V7yppU5TJg/cpPTmTZvM8k9vBuI1UArNI4d5thS49 S4RxZJi2VsUUTJGgJ/byAotBHijqc0a926mqd9E9y7oRv2m3x7HQjoE+bIUT6dHdiig== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=collabora.com; spf=pass smtp.mailfrom=collabora.com; dkim=pass header.d=collabora.com header.i=@collabora.com header.a=rsa-sha256 header.s=mail header.b="m/rwaVYR"; arc=none smtp.remote-ip=148.251.105.195 Received: from bali.collaboradmins.com (bali.collaboradmins.com [148.251.105.195]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7F111606A326; Fri, 6 Nov 2026 19:05:58 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 7F111606A326 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=collabora.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=collabora.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=collabora.com header.i=@collabora.com header.a=rsa-sha256 header.s=mail header.b=m/rwaVYR DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1793991956; bh=6LdXT14KOb6OCBtyF62RqXz9icJXVGvFn0shQuZytOU=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=m/rwaVYRyrhwiNzeDi/swPJtjeqJ6hzjz0zmjSpsv68KvWhW1dawlq7AtTJYMd2jO etDDXsOvYgoLbBFBtIuPEb+bHOXR8pFXqcyt5fHe4h9942XugEr6BUfACFw1ESD4Yv k87VluyvP3L0x9Fgpx0yzDJ/fVpqjzUT6ct7PU9CznK3Udf8lfhsWTeKoWtWfva9nz CaprmoSJvrXOPOk0SVzCGZTjbs27J5XpWj61DAYWuJzqtd+dtlvMFePjxuLiLC1o41 ompPNeaZPvJLVwyfROMxEea2+WvzxpbUpEJmmpyJQpAm/cQNARuB4ZOdnDh0xBO49X 9QqxIOIGV6KbQ== Received: from [100.64.0.214] (unknown [100.64.0.214]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange secp256r1 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: nicolas) by bali.collaboradmins.com (Postfix) with ESMTPSA id A66E617E0411; Fri, 06 Nov 2026 20:05:53 +0100 (CET) Message-ID: <2e69b386374ae46177a2fd975814a31e4016c3d9.camel@collabora.com> Subject: Re: [PATCH 7/7] media: qcom: iris: describe QC10C as TP10 From: Nicolas Dufresne To: rob.clark@oss.qualcomm.com Cc: Robert Mader , Dmitry Baryshkov , Dmitry Baryshkov , Abhinav Kumar , Jessica Zhang , Sean Paul , Marijn Suijten , David Airlie , Simona Vetter , Mauro Carvalho Chehab , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , Bryan O'Donoghue , Stanimir Varbanov , linux-arm-msm@vger.kernel.org, dri-devel@lists.freedesktop.org, freedreno@lists.freedesktop.org, linux-kernel@vger.kernel.org, Jordan Crouse , linux-media@vger.kernel.org, Vikash Garodia , Dikshita Agarwal , Neil Armstrong Date: Fri, 06 Nov 2026 14:05:51 -0500 In-Reply-To: References: <20261104-ubwc-format-docs-v1-0-389044012b4e@oss.qualcomm.com> <20261104-ubwc-format-docs-v1-7-389044012b4e@oss.qualcomm.com> <86b801ce-a56c-4ff8-8915-9be369fc0ce8@collabora.com> <062fe7dca00f77dac05197552d22897b28dc2143.camel@collabora.com> Autocrypt: addr=nicolas.dufresne@collabora.com; prefer-encrypt=mutual; keydata=mDMEaCN2ixYJKwYBBAHaRw8BAQdAM0EHepTful3JOIzcPv6ekHOenE1u0vDG1gdHFrChD /e0J05pY29sYXMgRHVmcmVzbmUgPG5pY29sYXNAbmR1ZnJlc25lLmNhPoicBBMWCgBEAhsDBQsJCA cCAiICBhUKCQgLAgQWAgMBAh4HAheABQkJZfd1FiEE7w1SgRXEw8IaBG8S2UGUUSlgcvQFAmibrjo CGQEACgkQ2UGUUSlgcvQlQwD/RjpU1SZYcKG6pnfnQ8ivgtTkGDRUJ8gP3fK7+XUjRNIA/iXfhXMN abIWxO2oCXKf3TdD7aQ4070KO6zSxIcxgNQFtDFOaWNvbGFzIER1ZnJlc25lIDxuaWNvbGFzLmR1Z nJlc25lQGNvbGxhYm9yYS5jb20+iJkEExYKAEECGwMFCwkIBwICIgIGFQoJCAsCBBYCAwECHgcCF4 AWIQTvDVKBFcTDwhoEbxLZQZRRKWBy9AUCaCyyxgUJCWX3dQAKCRDZQZRRKWBy9ARJAP96pFmLffZ smBUpkyVBfFAf+zq6BJt769R0al3kHvUKdgD9G7KAHuioxD2v6SX7idpIazjzx8b8rfzwTWyOQWHC AAS0LU5pY29sYXMgRHVmcmVzbmUgPG5pY29sYXMuZHVmcmVzbmVAZ21haWwuY29tPoiZBBMWCgBBF iEE7w1SgRXEw8IaBG8S2UGUUSlgcvQFAmibrGYCGwMFCQll93UFCwkIBwICIgIGFQoJCAsCBBYCAw ECHgcCF4AACgkQ2UGUUSlgcvRObgD/YnQjfi4+L8f4fI7p1pPMTwRTcaRdy6aqkKEmKsCArzQBAK8 bRLv9QjuqsE6oQZra/RB4widZPvphs78H0P6NmpIJ Organization: Collabora Canada Content-Type: multipart/signed; micalg="pgp-sha512"; protocol="application/pgp-signature"; boundary="=-XurZlOBuCgoi/+wYTJZt" User-Agent: Evolution 3.62.1 (3.62.1-1.fc45) X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 --=-XurZlOBuCgoi/+wYTJZt Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Hi Rob, Le jeudi 05 novembre 2026 =C3=A0 13:07 -0800, Rob Clark a =C3=A9crit=C2=A0: > On the v4l2 side, I'm not sure.=C2=A0 But it is also not clear to me if t= he > viddec hw (iris) supports all four combinations of P010/TP10 vs > linear/UBWC.=C2=A0 I guess there is already some fourcc translation neede= d > between v4l2 and drm, so maybe it is ok to stick with QC10C on the > v4l2 side? Commenting on this aspect specially, and Dmitry is really going in the righ= t direction, V4L2_PIX_FMT_QC08C and 4L2_PIX_FMT_QC10C was under specified, an= d so the implementation didn't have anything to be verified against. Just descri= bing what the format is and what kind of alignment is needed is a great start. T= he stride is not being used in practice by the importers (gpu and display), an= d I think we can turn that to our advantage. What I lately ask, is to just directly document for V4L2 users which fourcc+modifier should this v4l2 format map to. How many planes are expecte= d to be exposed, etc. When I naively asked, I thought the answer would have been unique and well known, but we uncovered issues. This comes from a simple ta= sk, that we must do for every V4L2 format in GStreamer, which is to map the format/modifier pair to its DRM format, as GStreamer negotiate DMABuf with = DRM formats these days. Whatever we tried, either failed to import in the GPU, = or failed in the display controller, due to interoperability issue, miss- interpretation. On your proposal, I'd like to highlight that NV12/TP10 usage is quite broke= n (though its fine if we have to live with that for backward compat, we'll co= de the exception). We commonly deduce the number of planes (or I should say the number of stri= des and offsets needed) from the base format. These two have 2 planes, but the = new doc states QC compressed has one plane. Same discussion happened with Arm a= nd Amlogic Frame Buffer Compression. They both are single plane, and for that reason DRM_FORMAT_YUV420_8BIT and DRM_FORMAT_YUV420_10BIT got introduced. T= hese don't have a linear representation, they reflect the depth, the subsampling= and are specified as single plane (single stride). The stride in AFBC is still allowed, to avoid forcing the width to be a padded width. The importers sho= uld walk backward the stride to find the padded width. QC compressed importer currently ignores the stride completely, so you have to have the padded wid= th. hope this helps, Nicolas --=-XurZlOBuCgoi/+wYTJZt Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part Content-Transfer-Encoding: 7bit -----BEGIN PGP SIGNATURE----- iHUEABYKAB0WIQTvDVKBFcTDwhoEbxLZQZRRKWBy9AUCau4lDwAKCRDZQZRRKWBy 9B09AQCiNR+l/1e2VeNu+RNjbJP0jSKScgnUcsZqLFd8m2lwlQEAgTgIn5070Dvr MBTt0SmP8C/5crzqIXMK409biSzy3gQ= =mcCx -----END PGP SIGNATURE----- --=-XurZlOBuCgoi/+wYTJZt--