From patchwork Mon Dec 18 14:57:58 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Maxime Ripard X-Patchwork-Id: 10119823 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id E711160327 for ; Mon, 18 Dec 2017 15:02:53 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id D8DCC28D6E for ; Mon, 18 Dec 2017 15:02:53 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id CD95128E27; Mon, 18 Dec 2017 15:02:53 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.2 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [65.50.211.133]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 505DE28D6E for ; Mon, 18 Dec 2017 15:02:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:MIME-Version:Cc:List-Subscribe: List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id: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=NMPNMhzqPuI9nzGPrJ4Q2JWjfwYgsbx/4vLUBaFfWCQ=; b=V3a+u41OlhSWmkbxHR1ff6B0kk mNp5s6GiPSazKAq+jOgK14yFucJvDmsra9nrGLjUEiJn5LfYDfUf2J1fzA/KotJAXvVrffgLlUAdq I+Ftj2kPzGf9HpgjQux5pWAIxKsEkCKF4QR7T29ObJb1RO8LdgfWD5x/vBv2IhAfmB2JdyWdS8rRO 2Eo2f14zWZL2habpuhJ5UNWUbHIPk0g3NIsXJrNhHSzxMahdd3iqKpeDAureD3XYtMYzjJycOn1xq krFRtiMUxjU4VwAowjs5So9Imdx/hwaJEp01weYGgVNFPgBas3rHfsl2Gg0VvOi7meN7PB5QcGT4s 8BOuFLtQ==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.89 #1 (Red Hat Linux)) id 1eQwwL-0003zR-OF; Mon, 18 Dec 2017 15:02:49 +0000 Received: from mail.free-electrons.com ([62.4.15.54]) by bombadil.infradead.org with esmtp (Exim 4.89 #1 (Red Hat Linux)) id 1eQws7-0008LI-8i for linux-arm-kernel@lists.infradead.org; Mon, 18 Dec 2017 14:58:39 +0000 Received: by mail.free-electrons.com (Postfix, from userid 110) id 1CE0A207C8; Mon, 18 Dec 2017 15:58:07 +0100 (CET) Received: from localhost (LStLambert-657-1-97-87.w90-63.abo.wanadoo.fr [90.63.216.87]) by mail.free-electrons.com (Postfix) with ESMTPSA id E92A020378; Mon, 18 Dec 2017 15:58:06 +0100 (CET) From: Maxime Ripard To: Daniel Vetter , David Airlie , Chen-Yu Tsai , Maxime Ripard Subject: [PATCH v2 11/12] drm/sun4i: backend: Make sure we don't have a commit pending Date: Mon, 18 Dec 2017 15:57:58 +0100 Message-Id: X-Mailer: git-send-email 2.14.3 In-Reply-To: References: In-Reply-To: References: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20171218_065828_093463_F014990D X-CRM114-Status: GOOD ( 12.94 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Thomas Petazzoni , narmstrong@baylibre.com, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-arm-kernel@lists.infradead.org, thomas@vitsch.nl MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP If we try to read the backend registers while it fetches the new values, we end up with the value of some random register instead of the one we asked for. In order to prevent that, let's make sure that the very first thing we do during our atomic modesetting is to let the commit bit come to a rest. We don't have to worry about anything else since the only time we will trigger a new transaction is during the atomic_commit which comes much later. Signed-off-by: Maxime Ripard Reviewed-by: Chen-Yu Tsai --- drivers/gpu/drm/sun4i/sun4i_backend.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/drivers/gpu/drm/sun4i/sun4i_backend.c b/drivers/gpu/drm/sun4i/sun4i_backend.c index 4642f933765e..a18c86a15748 100644 --- a/drivers/gpu/drm/sun4i/sun4i_backend.c +++ b/drivers/gpu/drm/sun4i/sun4i_backend.c @@ -297,6 +297,17 @@ static bool sun4i_backend_plane_uses_frontend(struct drm_plane_state *state) return sun4i_backend_plane_uses_scaler(state); } +static void sun4i_backend_atomic_begin(struct sunxi_engine *engine, + struct drm_crtc_state *old_state) +{ + u32 val; + + WARN_ON(regmap_read_poll_timeout(engine->regs, + SUN4I_BACKEND_REGBUFFCTL_REG, + val, !(val & SUN4I_BACKEND_REGBUFFCTL_LOADCTL), + 100, 50000)); +} + static int sun4i_backend_atomic_check(struct sunxi_engine *engine, struct drm_crtc_state *crtc_state) { @@ -478,6 +489,7 @@ static struct sun4i_frontend *sun4i_backend_find_frontend(struct sun4i_drv *drv, } static const struct sunxi_engine_ops sun4i_backend_engine_ops = { + .atomic_begin = sun4i_backend_atomic_begin, .atomic_check = sun4i_backend_atomic_check, .commit = sun4i_backend_commit, .layers_init = sun4i_layers_init,