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 X-Spam-Level: X-Spam-Status: No, score=-12.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B0896C43467 for ; Thu, 8 Oct 2020 11:27:09 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 28AEB2145D for ; Thu, 8 Oct 2020 11:27:09 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="WeQRn0G1"; dkim=temperror (0-bit key) header.d=cerno.tech header.i=@cerno.tech header.b="IrWmdEI5"; dkim=temperror (0-bit key) header.d=messagingengine.com header.i=@messagingengine.com header.b="jo/06Igj" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 28AEB2145D Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=cerno.tech Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To:Message-Id:Date: Subject:To:From:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=J+ChV/IItjs7zSwfVZJC8gZPBUcWatURPsBzIn/XxEg=; b=WeQRn0G1Ztvz1ua9b7+ybkb2r lVZNActVEzI2SRJqs4X+9KHbeVsuL9oRL+Nmm2BfRQedM6YEUWwReCIL5NDMtHHhtLqb7WncJ5RJs Z0GX/pnDhy4cTs5/XON9dArL8V+oQGBJl474pJBJXlpHhSWwV81yJiYo18ScL/yvGSbGrHHZ8jlvZ mV6n917dET92xXctmaCzT8AcvazMWQ0K4csAiBhV1wsHo/XsI+1+UVnPrXoVCYWRs+LI4M/9skzSX FyXcwtp9x90UntQaWZ0FOMj8PmCuEAm57+Fzb7KusyPLIJ/jwIUS2ykj0W4L7fF+/M56IT1ySgV9N gi56v4Aww==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kQU3D-0001Lq-Ev; Thu, 08 Oct 2020 11:25:35 +0000 Received: from new2-smtp.messagingengine.com ([66.111.4.224]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1kQU37-0001Iy-Sy; Thu, 08 Oct 2020 11:25:31 +0000 Received: from compute6.internal (compute6.nyi.internal [10.202.2.46]) by mailnew.nyi.internal (Postfix) with ESMTP id B3B0058030D; Thu, 8 Oct 2020 07:25:25 -0400 (EDT) Received: from mailfrontend2 ([10.202.2.163]) by compute6.internal (MEProxy); Thu, 08 Oct 2020 07:25:25 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cerno.tech; h= from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; s=fm1; bh=9MjtOof5vkiRK D0pvzPXMjb11wuehn5KVP/NaCvxQEE=; b=IrWmdEI5jn00DmOb+uEDDHHmVl1GV oOdIOH6jW+jh2RhktaLhwWVEMm4+LVgnPiwNFSkWO6CiT35thcptfEMbwNgztsh4 xxVVOlk3Xs36MLIpp+5I/w7eit1FS2+Lambmyr4Lid0OBiEPzPMv/61Bq2elfCp8 gRSu8LXJBV54EQQd7isG4jV5fPpsWt+ExFXEZLdTNlcqpZgCul7T8asWsp+gAEqe 3zgLG4Zck+EIuUtWmgV/5VvqN+hvdedKgZdOPbTJ4kuK53TaXn0KT9lG7RJpZRIh ChthsOFSy+UWk6/9uSUtmvG2E8V+PhutNc6RKbiFGh/ZMG2TPAVJ9U0MQ== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:content-transfer-encoding:date:from :in-reply-to:message-id:mime-version:references:subject:to :x-me-proxy:x-me-proxy:x-me-sender:x-me-sender:x-sasl-enc; s= fm1; bh=9MjtOof5vkiRKD0pvzPXMjb11wuehn5KVP/NaCvxQEE=; b=jo/06Igj wHgVf8yzBpjcD2haP1bmqHYHoPf1dk1OWO5jJSodFcqF4m8N9JJcAwjjPUkadT6Z tvrlZjOGK8txSD+txdNigq7Pw/+OgzbO9dlLxGO+skB2FOCHHsXBRTam/jBQeLrb b4p68/MFf58fxizccbLVeXqSdQFry6AV4gX4HJIRlPFV8e6CRB9iGFNgh4IjHIcJ J0Ym7YwoYBqwP2AYULShYZwJZT+mgQ/eAxEJ/Rlgp+OXvxQLPMZ+MJKLAu9ulnr2 JUyvZ1x0j4+kqi2ISdGBixOXJAU6RMX4Sec4g/mjHDrPVPyH8enF6RL1wfH+aPal CrARgjlhiiSfRw== X-ME-Sender: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgedujedrgeelgddufecutefuodetggdotefrodftvf curfhrohhfihhlvgemucfhrghsthforghilhdpqfgfvfdpuffrtefokffrpgfnqfghnecu uegrihhlohhuthemuceftddtnecusecvtfgvtghiphhivghnthhsucdlqddutddtmdenuc fjughrpefhvffufffkofgjfhgggfestdekredtredttdenucfhrhhomhepofgrgihimhgv ucftihhprghrugcuoehmrgigihhmvgestggvrhhnohdrthgvtghhqeenucggtffrrghtth gvrhhnpedvkeelveefffekjefhffeuleetleefudeifeehuddugffghffhffehveevheeh vdenucfkphepledtrdekledrieekrdejieenucevlhhushhtvghrufhiiigvpedtnecurf grrhgrmhepmhgrihhlfhhrohhmpehmrgigihhmvgestggvrhhnohdrthgvtghh X-ME-Proxy: Received: from localhost (lfbn-tou-1-1502-76.w90-89.abo.wanadoo.fr [90.89.68.76]) by mail.messagingengine.com (Postfix) with ESMTPA id 70B563064682; Thu, 8 Oct 2020 07:25:23 -0400 (EDT) From: Maxime Ripard To: Mark Rutland , Rob Herring , Frank Rowand , Daniel Vetter , David Airlie , Maarten Lankhorst , Thomas Zimmermann , Maxime Ripard , Eric Anholt Subject: [PATCH 2/4] drm/vc4: kms: Document the muxing corner cases Date: Thu, 8 Oct 2020 13:25:17 +0200 Message-Id: <20201008112519.43691-2-maxime@cerno.tech> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20201008112519.43691-1-maxime@cerno.tech> References: <20201008112519.43691-1-maxime@cerno.tech> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20201008_072530_003578_FD407760 X-CRM114-Status: GOOD ( 16.85 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: devicetree@vger.kernel.org, Tim Gover , Dave Stevenson , dri-devel@lists.freedesktop.org, Hoegeun Kwon , bcm-kernel-feedback-list@broadcom.com, linux-rpi-kernel@lists.infradead.org, Phil Elwell , linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org We've had a number of muxing corner-cases with specific ways to reproduce them, so let's document them to make sure they aren't lost and introduce regressions later on. Signed-off-by: Maxime Ripard --- drivers/gpu/drm/vc4/vc4_kms.c | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) diff --git a/drivers/gpu/drm/vc4/vc4_kms.c b/drivers/gpu/drm/vc4/vc4_kms.c index 846fe8b3cb7a..3b5e62842901 100644 --- a/drivers/gpu/drm/vc4/vc4_kms.c +++ b/drivers/gpu/drm/vc4/vc4_kms.c @@ -612,6 +612,28 @@ static const struct drm_private_state_funcs vc4_load_tracker_state_funcs = { #define NUM_OUTPUTS 6 #define NUM_CHANNELS 3 +/* + * The BCM2711 HVS has up to 7 output connected to the pixelvalves and + * the TXP (and therefore all the CRTCs found on that platform). + * + * The naive (and our initial) implementation would just iterate over + * all the active CRTCs, try to find a suitable FIFO, and then remove it + * from the available FIFOs pool. However, there's a few corner cases + * that need to be considered: + * + * - When running in a dual-display setup (so with two CRTCs involved), + * we can update the state of a single CRTC (for example by changing + * its mode using xrandr under X11) without affecting the other. In + * this case, the other CRTC wouldn't be in the state at all, so we + * need to consider all the running CRTCs in the DRM device to assign + * a FIFO, not just the one in the state. + * + * - Since we need the pixelvalve to be disabled and enabled back when + * the FIFO is changed, we should keep the FIFO assigned for as long + * as the CRTC is enabled, only considering it free again once that + * CRTC has been disabled. This can be tested by booting X11 on a + * single display, and changing the resolution down and then back up. + */ static int vc4_pv_muxing_atomic_check(struct drm_device *dev, struct drm_atomic_state *state) { -- 2.26.2 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel