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 69ED3C02180 for ; Wed, 15 Jan 2025 12:43:54 +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=1RcxtxlumVu95tJe16ZNT9MbHCNTWy4EKh6cp1RBw60=; b=FDsDYAYdWkinhNvjMO33j723IF NGZocszdLHaV0NeuQsdAfEJhsh3k5pfwt2TYMMZHwypSyDIEwggy+XycZH+AyaG8b3SJEJeOKCws+ 6voN/WofBBXIWSA+DBqle5DAzm7pvWKUfjzWGRxgPUkfhwV5NsFTjehGADVh+XESFMUIJ4gAt6Fqa e/djuYHTa3/acS6uHOnB0djB25qIMY+G1sA+IuQ4RSUaudzT8Rm8bdniXs/0+hKwnzLme/RbbZaQj danf+3NkqJJUJ3h3Rg6+BYtO78F/PjdR/kSLg1Lbz1wmesh6k7XC8eVDi8YsKEqI4KYfNxgoayVGW TwNQ+mog==; 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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-20250115_044222_674264_CCA4661D X-CRM114-Status: GOOD ( 18.53 ) X-BeenThere: linux-arm-kernel@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-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi, On 15/01/2025 14:33, Geert Uytterhoeven wrote: > Hi Tomi, > > On Wed, Jan 15, 2025 at 12:11 PM Tomi Valkeinen > wrote: >> On 15/01/2025 12:33, Geert Uytterhoeven wrote: >>> On Wed, Jan 15, 2025 at 10:04 AM Tomi Valkeinen >>> wrote: >>>> Add Y10_LE32, a 10 bit greyscale format, with 3 pixels packed into >>>> 32-bit container. >>>> >>>> Signed-off-by: Tomi Valkeinen >>> >>> Thanks for your patch! >>> >>>> --- a/include/uapi/drm/drm_fourcc.h >>>> +++ b/include/uapi/drm/drm_fourcc.h >>>> @@ -408,6 +408,7 @@ extern "C" { >>>> /* Greyscale formats */ >>>> >>>> #define DRM_FORMAT_Y8 fourcc_code('G', 'R', 'E', 'Y') /* 8-bit Y-only */ >>>> +#define DRM_FORMAT_Y10_LE32 fourcc_code('Y', 'P', 'A', '4') /* [31:0] x:Y2:Y1:Y0 2:10:10:10 little endian */ >>> >>> R10_LE32? Or R10_PA4? >> >> Can we discuss the "R" vs "Y" question under the cover letter? There's >> some more context about it in there. > > Sorry, hadn't read the cover letter. I got attracted by "Y8" and "Y10". > >> I took the "LE32" from Gstreamer's format. Maybe it's a bit pointless. >> >> I don't know if it makes sense to add the fourcc to the DRM format name. >> The fourcc is very limited. Rather, we could, say, have >> DRM_FORMAT_Y10_PACKED_32 (or "R", if you insist =). >> >>> Does LE32 have a meaning? My first guess just reading the subject >>> was wrong ("little endian 32-bit" ;-) >> >> I'm not sure I follow. It's little-endian. The pixel group/unit is a >> 32-bit number, where the leftmost pixel on the screen is in bits 9-0, >> and the padding is in bits 31-30, and stored in memory as little-endian. > > Ah, the "LE" applies to the pixels inside each word. No, to the 32-bit container. > DRM formats stored in memory are always little-endian, unless the > DRM_FORMAT_BIG_ENDIAN bit is set, which is what I was hinting > at... Indeed you're right. The "LE" is pointless. So back to the bike-shedding about the name =). Tomi