From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 883ACFC592E for ; Thu, 26 Feb 2026 11:04:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=BWCo0kG96iv+7s5TDWEYgj7Bqm4OdYUx2iwx1W1m2LI=; b=uw6ALt32W5DdQDa3Dj0ohN93Bz iwCbn4DgYz6JGFroW2WydUiaY8qxgXP2hZ9vTwChcrCVzgWjVdJrfcdKznwH2gNK4a3uXFAB7bFwp jpiu5SRK2+KuPBcQGsvVeEcxXZMPXSwyhuc718OdQPds68qXAthlwg/h8RtcezAmJDMJAa9S+tgo8 QnqbivO+9pr0TotcTafOMHzn1mmP+O1whZc1R+B/5vt9/CQrmuXBV0rYPXvz893P36tLimQ2Dqeeg NXb4mwfKX+tbXjjP3+YbXEnXADNl64yKwb+n0BasgXQBETrh0c+gC6rbhv+lkbChNFUElx3CgU+UA Jp3cqdXg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vvYa0-00000005uN0-2XyD; Thu, 26 Feb 2026 10:26:48 +0000 Received: from bali.collaboradmins.com ([148.251.105.195]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1vvYZs-00000005uKT-1xx5; Thu, 26 Feb 2026 10:26:41 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1772101597; bh=3eCyIbVoYn9bRaJqczY4pr5CznMSS3V4x87uwrFbJ8c=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=MjUnMuyP3A9OINHEM1o5EkAlqs43uO4wcutkdSRek77KS0YwY3w3YUluDbMw5H2qe 0Mg5JjkP471JwsyMgSNKGGMGHDGYxopjSBAwog7VoL7ySRUlyS5D6fyDMR2ieD9/c6 5aMFlxvr8ahCmIRQh0bFwDKwTe8mZD0MtR/0n7O1g27CJmNkQjpysBwem3bfcYW20g 4q2FQQ/Dp/efBlcZPJpNsdsQCvK+Op4uFUhq03ZqjBuNElbeYCFunPUhuRXlmuskqP puec1xwDeGqNwkefR0voO3Ys3h4r6f+wTL6b2fQy790CVJCg0RKVfUQI1by3qx5J9P quH1qqZTClrQQ== Received: from [192.168.1.100] (2-237-20-237.ip236.fastwebnet.it [2.237.20.237]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: kholk11) by bali.collaboradmins.com (Postfix) with ESMTPSA id 3494A17E0097; Thu, 26 Feb 2026 11:26:37 +0100 (CET) Message-ID: <2e241629-2526-41c5-92fd-a0a0ec3ffc4e@collabora.com> Date: Thu, 26 Feb 2026 11:26:36 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 00/11] Plane Color Pipeline support for MediaTek To: =?UTF-8?B?Q0sgSHUgKOiDoeS/iuWFiSk=?= , "pekka.paalanen@collabora.com" , Nicolas Prado , "harry.wentland@amd.com" Cc: "wiagn233@outlook.com" , "tzimmermann@suse.de" , "simona@ffwll.ch" , "mripard@kernel.org" , Daniel Stone , "linux-mediatek@lists.infradead.org" , "maarten.lankhorst@linux.intel.com" , "dri-devel@lists.freedesktop.org" , "linux-kernel@vger.kernel.org" , "chunkuang.hu@kernel.org" , "kernel@collabora.com" , Ariel D'Alessandro , "p.zabel@pengutronix.de" , "xaver.hugl@gmail.com" , "linux-arm-kernel@lists.infradead.org" , "airlied@gmail.com" , "matthias.bgg@gmail.com" References: <20251223-mtk-ovl-pre-blend-colorops-v1-0-0cb99bd0ab33@collabora.com> <20260206110901.660cf712@eldfell> <5963bca37996fa054ad75d4e5017d9c7e5158e9f.camel@collabora.com> <3efaa7ec40c68f0d463da00c3a57474a40d4fdae.camel@mediatek.com> From: AngeloGioacchino Del Regno Content-Language: en-US In-Reply-To: <3efaa7ec40c68f0d463da00c3a57474a40d4fdae.camel@mediatek.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260226_022640_656025_F1AD2DF2 X-CRM114-Status: GOOD ( 24.59 ) X-BeenThere: linux-mediatek@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-mediatek" Errors-To: linux-mediatek-bounces+linux-mediatek=archiver.kernel.org@lists.infradead.org Il 26/02/26 07:24, CK Hu (胡俊光) ha scritto: > On Fri, 2026-02-06 at 08:28 -0500, Nícolas F. R. A. Prado wrote: >> On Fri, 2026-02-06 at 11:09 +0200, Pekka Paalanen wrote: >>> On Fri, 2 Jan 2026 13:40:21 -0500 >>> Harry Wentland wrote: >>> >>>> On 2026-01-01 07:37, Shengyu Qu wrote: >>>>> >>>>> >>>>> 在 2025/12/30 02:53, Shengyu Qu 写道: >>>>>> >>>>>> >>>>>> 在 2025/12/24 3:44, NÃ colas F. R. A. Prado 写道: >>> >>>>>>> Given the lack of support for writeback connectors on the >>>>>>> MediaTek KMS driver, combined with limited hardware >>>>>>> documentation, I haven't been able to verify the correctness >>>>>>> of >>>>>>> each curve, only that they were visually sane (gamma curves >>>>>>> made >>>>>>> the image on the display brighter, while inverse gamma made >>>>>>> it >>>>>>> darker). >>>>>> >>>>>> Hmmm I don't think this is acceptable. sRGB/scRGB has two >>>>>> transfer >>>>>> functions mentioned in original specification[1]. To keep color >>>>>> accuracy, we need someone from mediatek confirm whether this is >>>>>> piece- wise or pure power 2.2 transfer function, this is >>>>>> already >>>>>> done in original amdgpu color pipeline series, sRGB means >>>>>> piece-wise while also dedicated power 2.2 function exists. >>>> >>>> Not sure what you mean with this not being acceptable. This is >>>> about >>>> enabling HW support for this functionality. Not every HW has >>>> writeback for testing. At some point you'll have to trust the >>>> driver >>>> devs if you're going to use functionality of the driver. We're not >>>> always going to get everything perfect, but if that's really such a >>>> worry you can always use shaders to do precisely what you want. >>>> >>> >>> Hi Harry, >>> >>> yes, but I understood that in this case, the hardware documentation >>> available is so vague that it's impossible to say what it will >>> actually >>> do. There are no formulas given or referenced in the documentation, >>> are >>> there, Nícolas? >> >> No formulas at all, the only documentation I had available for the >> curves was the register definition, which simply lists the possible >> values: SCRGB, BT709, BT2020, HLG. > > Hi, Nicolas: > > In [1], it shows OVL could output data to WDMA which could write data into DRAM. > Its control is similar to RDMA. RDMA read data from DRAM and WDMA write data into DRAM. > Do you have interest to implement WDMA? I wrote a WDMA driver a long ago, but I couldn't get it to work (though, I admit I didn't try hard to actually get it working).... if you want to take a look to check if anything obvious is missing, the driver is here: https://gitlab.collabora.com/mediatek/aiot/linux/-/blob/mediatek-dev/drivers/gpu/drm/mediatek/mtk_disp_wdma.c?ref_type=heads The driver I wrote was supposed to work on MT8781 Helio G99 (for a personal project as in upstreaming of the Xiaomi Poco M5 smartphone) and on MT8195 as a PoC. I did test both platforms and this driver didn't work on both... not sure if that was because I misconfigured the MMSYS routing (on both) or if there's any actual issue with the driver I wrote. Again, didn't invest much time on this, anyway, so some obvious issue might be present. Cheers, Angelo > This is just a suggestion. > I could accept we believe what document say first and wait for someone to verify it. > > [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/soc/mediatek/mt8195-mmsys.h?h=v7.0-rc1#n8 > > Regards, > CK > >> >