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 gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (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 1CFD1C433F5 for ; Mon, 2 May 2022 14:25:56 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 173BE10EBAA; Mon, 2 May 2022 14:25:54 +0000 (UTC) Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.220.28]) by gabe.freedesktop.org (Postfix) with ESMTPS id B847610EB66 for ; Mon, 2 May 2022 14:25:52 +0000 (UTC) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id 0DB3F21878; Mon, 2 May 2022 14:25:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1651501529; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=kNEgVJyAXiUeJ1SSdQu3qjRW9AgTLMm5aqAXX4dowOM=; b=Lu2AHhWDWBoBQT368HT//SpdbAYI3FfR9J7yty8lYXx+zSpjPDtNKev/pCHqINwjjC/adX sf1azsVwyym6r4J7Hu9KCZUvPEsVvajtVCM6VRBx0K6KnxUe9fy7fxKXSgFm5CsA1oAv5y Fy8kZXdw2cDxWhXd4rkxk0ziAdniGnE= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1651501529; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=kNEgVJyAXiUeJ1SSdQu3qjRW9AgTLMm5aqAXX4dowOM=; b=8BB+UG+LZJS1mCsyBT4VTyQuW/8vgZl7RNqnLcwrfuIk22dnGt9ZFBq0RYsc4XvgI60Cek OUE3cq+TGHHTD/DQ== Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id DEC0213B0F; Mon, 2 May 2022 14:25:28 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id EIemNdjpb2J4MgAAMHmgww (envelope-from ); Mon, 02 May 2022 14:25:28 +0000 From: Thomas Zimmermann To: airlied@redhat.com, airlied@linux.ie, daniel@ffwll.ch, maarten.lankhorst@linux.intel.com, mripard@kernel.org Subject: [PATCH 3/3] drm/mgag200: Protect concurrent access to I/O registers with lock Date: Mon, 2 May 2022 16:25:14 +0200 Message-Id: <20220502142514.2174-4-tzimmermann@suse.de> X-Mailer: git-send-email 2.36.0 In-Reply-To: <20220502142514.2174-1-tzimmermann@suse.de> References: <20220502142514.2174-1-tzimmermann@suse.de> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Thomas Zimmermann , dri-devel@lists.freedesktop.org Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" Add a mutex lock to protect concurrent access to I/O registers against each other. This happens between invokataion of commit- tail functions and get-mode operations. Both with use the CRTC index registers MGA1064_GEN_IO_DATA and MGA1064_GEN_IO_CTL. Concurrent access can lead to failed mode-setting operations. Signed-off-by: Thomas Zimmermann --- drivers/gpu/drm/mgag200/mgag200_drv.c | 6 ++++++ drivers/gpu/drm/mgag200/mgag200_drv.h | 1 + drivers/gpu/drm/mgag200/mgag200_mode.c | 14 ++++++++++++++ 3 files changed, 21 insertions(+) diff --git a/drivers/gpu/drm/mgag200/mgag200_drv.c b/drivers/gpu/drm/mgag200/mgag200_drv.c index 217844d71ab5c..08839460606fe 100644 --- a/drivers/gpu/drm/mgag200/mgag200_drv.c +++ b/drivers/gpu/drm/mgag200/mgag200_drv.c @@ -14,6 +14,7 @@ #include #include #include +#include #include #include @@ -65,6 +66,11 @@ static int mgag200_regs_init(struct mga_device *mdev) struct pci_dev *pdev = to_pci_dev(dev->dev); u32 option, option2; u8 crtcext3; + int ret; + + ret = drmm_mutex_init(dev, &mdev->rmmio_lock); + if (ret) + return ret; switch (mdev->type) { case G200_PCI: diff --git a/drivers/gpu/drm/mgag200/mgag200_drv.h b/drivers/gpu/drm/mgag200/mgag200_drv.h index 4368112023f7c..18829eb8398a0 100644 --- a/drivers/gpu/drm/mgag200/mgag200_drv.h +++ b/drivers/gpu/drm/mgag200/mgag200_drv.h @@ -213,6 +213,7 @@ struct mga_device { struct drm_device base; unsigned long flags; + struct mutex rmmio_lock; resource_size_t rmmio_base; resource_size_t rmmio_size; void __iomem *rmmio; diff --git a/drivers/gpu/drm/mgag200/mgag200_mode.c b/drivers/gpu/drm/mgag200/mgag200_mode.c index 6e18d3bbd7207..abde7655477db 100644 --- a/drivers/gpu/drm/mgag200/mgag200_mode.c +++ b/drivers/gpu/drm/mgag200/mgag200_mode.c @@ -881,6 +881,14 @@ mgag200_simple_display_pipe_enable(struct drm_simple_display_pipe *pipe, .y2 = fb->height, }; + /* + * Concurrent operations could possibly trigger a call to + * drm_connector_helper_funcs.get_modes by trying to read the + * display modes. Protect access to I/O registers by acquiring + * the I/O-register lock. + */ + mutex_lock(&mdev->rmmio_lock); + if (mdev->type == G200_WB || mdev->type == G200_EW3) mgag200_g200wb_hold_bmc(mdev); @@ -904,6 +912,8 @@ mgag200_simple_display_pipe_enable(struct drm_simple_display_pipe *pipe, mgag200_enable_display(mdev); mgag200_handle_damage(mdev, fb, &fullscreen, &shadow_plane_state->data[0]); + + mutex_unlock(&mdev->rmmio_lock); } static void @@ -963,8 +973,12 @@ mgag200_simple_display_pipe_update(struct drm_simple_display_pipe *pipe, if (!fb) return; + mutex_lock(&mdev->rmmio_lock); + if (drm_atomic_helper_damage_merged(old_state, state, &damage)) mgag200_handle_damage(mdev, fb, &damage, &shadow_plane_state->data[0]); + + mutex_unlock(&mdev->rmmio_lock); } static struct drm_crtc_state * -- 2.36.0