From patchwork Thu Jun 12 14:59:20 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kaustabh Chakraborty X-Patchwork-Id: 896219 Received: from layka.disroot.org (layka.disroot.org [178.21.23.139]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8CAF3289839; Thu, 12 Jun 2025 15:01:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=178.21.23.139 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749740482; cv=none; b=V73SM+H2TkjuiWNbf6Vp+igohocfgxFtGkMFMD0sAoMUT1sjS+9+2uEZtpcTSZsq6L0ph4n19fcK0ZXIZuul+cGceWOkMjpicxiaZYaQGeOL7e7U2SE1RYclExwKqmLWgdsECtPkFmdWbWQ4jn6OLS3u2PUwSds2RoQA5qO+Njg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749740482; c=relaxed/simple; bh=D8o5aKxiqPDfJaP/Wlra9wiusUGgyAqkKg4+LuSvXis=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=R0h61lwUAWaHHCr/1VnTDAbN3Lf+IBBpxYnY16QCxhTg+d31GwsYDo8yVkJIqXrwHzIl8RFZvSk4KUKdxR4PX8qbWKwNeF74JA6Wtg2HXEZ+qa11eDMD3VPwJpQCIlrIEqrF8WTFy6xpw5FDLSI1vV07aUguQYQ3Pc/t8Hmtcds= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=disroot.org; spf=pass smtp.mailfrom=disroot.org; dkim=pass (2048-bit key) header.d=disroot.org header.i=@disroot.org header.b=bn6KTEPY; arc=none smtp.client-ip=178.21.23.139 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=disroot.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=disroot.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=disroot.org header.i=@disroot.org header.b="bn6KTEPY" Received: from mail01.disroot.lan (localhost [127.0.0.1]) by disroot.org (Postfix) with ESMTP id 175ED25F66; Thu, 12 Jun 2025 17:01:19 +0200 (CEST) X-Virus-Scanned: SPAM Filter at disroot.org Received: from layka.disroot.org ([127.0.0.1]) by localhost (disroot.org [127.0.0.1]) (amavis, port 10024) with ESMTP id cJPnsxm7-FXg; Thu, 12 Jun 2025 17:01:18 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=disroot.org; s=mail; t=1749740451; bh=D8o5aKxiqPDfJaP/Wlra9wiusUGgyAqkKg4+LuSvXis=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=bn6KTEPYJhfvaGt2QBHkIbHgJCb0CRBaJ/IOnV4I4/F+ritPtnyNle5ZETilDMpKH wlskdq4ZogKkt4ZQUyt5ACHvpcTI8ns3LoPm6eozssU35Mty+H9IrEEcjFrgUVoQXc Q0OZlDCF5bT//0HqW3WkfhdCinrYgtsZqm88DDfKzT9Q3p12/NJOoAaK4s8N8yNFLC chsw/wkVS/0aA2e3ZwErcEuwCtIBHyLLhpdeKlLMFhUGRvO80txL6l9d91prm4OS+5 6u3RgLDsXztehL5tc6nx1BgdnbrIKc9//oTT0A57cT3cCZRqPhAYj0U+8dv1MBY78+ JVwwxiTm0bp7w== From: Kaustabh Chakraborty Date: Thu, 12 Jun 2025 20:29:20 +0530 Subject: [PATCH v2 2/2] drm/exynos: exynos7_drm_decon: add vblank check in IRQ handling Precedence: bulk X-Mailing-List: linux-samsung-soc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <20250612-exynosdrm-decon-v2-2-d6c1d21c8057@disroot.org> References: <20250612-exynosdrm-decon-v2-0-d6c1d21c8057@disroot.org> In-Reply-To: <20250612-exynosdrm-decon-v2-0-d6c1d21c8057@disroot.org> To: Inki Dae , Seung-Woo Kim , Kyungmin Park , David Airlie , Simona Vetter , Krzysztof Kozlowski , Alim Akhtar , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , Rob Herring , Conor Dooley , Ajay Kumar , Akshu Agrawal Cc: dri-devel@lists.freedesktop.org, linux-arm-kernel@lists.infradead.org, linux-samsung-soc@vger.kernel.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, Kaustabh Chakraborty , stable@vger.kernel.org X-Developer-Signature: v=1; a=ed25519-sha256; t=1749740428; l=1467; i=kauschluss@disroot.org; s=20250202; h=from:subject:message-id; bh=D8o5aKxiqPDfJaP/Wlra9wiusUGgyAqkKg4+LuSvXis=; b=e+o8Wo7jtjYn2hZT25bsk7JQTuoWvuRvUzHVhB4xhIPbD24Y+LwjAiDqnP5zIbfSGS0+N8Epw 4T77CIPXp6GCgnmWlOdaABdsRVXGTKb/4QHtsL0yevgkRsR90EloPvb X-Developer-Key: i=kauschluss@disroot.org; a=ed25519; pk=h2xeR+V2I1+GrfDPAhZa3M+NWA0Cnbdkkq1bH3ct1hE= If there's support for another console device (such as a TTY serial), the kernel occasionally panics during boot. The panic message and a relevant snippet of the call stack is as follows: Unable to handle kernel NULL pointer dereference at virtual address 000000000000000 Call trace: drm_crtc_handle_vblank+0x10/0x30 (P) decon_irq_handler+0x88/0xb4 [...] Otherwise, the panics don't happen. This indicates that it's some sort of race condition. Add a check to validate if the drm device can handle vblanks before calling drm_crtc_handle_vblank() to avoid this. Cc: stable@vger.kernel.org Fixes: 96976c3d9aff ("drm/exynos: Add DECON driver") Signed-off-by: Kaustabh Chakraborty --- drivers/gpu/drm/exynos/exynos7_drm_decon.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/gpu/drm/exynos/exynos7_drm_decon.c b/drivers/gpu/drm/exynos/exynos7_drm_decon.c index 43bcbe2e2917df43d7c2d27a9771e892628dd682..c0c0f23169c993ac315fc8d7bcbd09ea6ec9966a 100644 --- a/drivers/gpu/drm/exynos/exynos7_drm_decon.c +++ b/drivers/gpu/drm/exynos/exynos7_drm_decon.c @@ -636,6 +636,10 @@ static irqreturn_t decon_irq_handler(int irq, void *dev_id) if (!ctx->drm_dev) goto out; + /* check if crtc and vblank have been initialized properly */ + if (!drm_dev_has_vblank(ctx->drm_dev)) + goto out; + if (!ctx->i80_if) { drm_crtc_handle_vblank(&ctx->crtc->base);