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 5E7E7CD484E for ; Tue, 12 May 2026 06:02:42 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 0F26D10E56C; Tue, 12 May 2026 06:02:42 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=intel.com header.i=@intel.com header.b="aye+w6xQ"; dkim-atps=neutral Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.10]) by gabe.freedesktop.org (Postfix) with ESMTPS id 0DD6910E56C for ; Tue, 12 May 2026 06:02:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1778565761; x=1810101761; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=9HP0FyZTcIxQhvV/IhRkajoIeV5qXRCPWOdd9QwP/uM=; b=aye+w6xQ034I6COm/aKYW43ZvHRjNIYwpgaUpxdF756aSzZO+znp3QM+ qSrw6BCWk6dJW45Wi8uQ8PEgyTrbWrIUZkf5OuoBXQX4LrPtMjuK/qZDL gP9A2A3AauaFi5TWhoZJz2v8A4JT6vXhj0PMPRNbfYfEbsNIi1ZEbafbC GI1Wr+PE+klEhjwXN9m4aTrErkzZFnJ4AVMlmf8wCRPWr+9OQY2Nij9q4 TObA35iuT1jKWhoJt8uacYQlnLjeHLRteQNcDRKFTZbl6eLyazXHtlpdl Cs8lCuP9ckA66PFMTHa7R4DOLqm17h2a6bPhboLvFK8BbYvgVJwGOdJUq A==; X-CSE-ConnectionGUID: H493OThQSsSxPCEQOVmLcA== X-CSE-MsgGUID: aEe/nHiTRvuzooHhj9Xbew== X-IronPort-AV: E=McAfee;i="6800,10657,11783"; a="90848974" X-IronPort-AV: E=Sophos;i="6.23,230,1770624000"; d="scan'208";a="90848974" Received: from orviesa005.jf.intel.com ([10.64.159.145]) by fmvoesa104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 11 May 2026 23:02:40 -0700 X-CSE-ConnectionGUID: 5QUhRToMRyqfapyzrbbX/A== X-CSE-MsgGUID: INpX46DaRReF6Yg2paFXaA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.23,230,1770624000"; d="scan'208";a="242670578" Received: from srr4-3-linux-106-armuthy.iind.intel.com ([10.190.238.56]) by orviesa005.jf.intel.com with ESMTP; 11 May 2026 23:02:40 -0700 From: Arun R Murthy To: intel-xe@lists.freedesktop.org Cc: rodrigo.vivi@intel.com, lucas.demarchi@intel.com, Arun R Murthy Subject: [PATCH] drm/xe: Check for dead config space on reading all 1s Date: Tue, 12 May 2026 11:31:28 +0530 Message-Id: <20260512060128.209698-1-arun.r.murthy@intel.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-BeenThere: intel-xe@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel Xe graphics driver List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-xe-bounces@lists.freedesktop.org Sender: "Intel-xe" Reading the VF_CAP returns all 1s when the config space is dead leading to missdetection of VF and confusing the GuC. Check for all 1s and pci device detect can act as a sanity. Closes: https://gitlab.freedesktop.org/drm/xe/kernel/-/work_items/7941 Signed-off-by: Arun R Murthy --- drivers/gpu/drm/xe/xe_sriov.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/drivers/gpu/drm/xe/xe_sriov.c b/drivers/gpu/drm/xe/xe_sriov.c index f3835867fce5..40e142d78924 100644 --- a/drivers/gpu/drm/xe/xe_sriov.c +++ b/drivers/gpu/drm/xe/xe_sriov.c @@ -4,6 +4,7 @@ */ #include +#include #include @@ -39,8 +40,21 @@ const char *xe_sriov_mode_to_string(enum xe_sriov_mode mode) static bool test_is_vf(struct xe_device *xe) { + struct pci_dev *pdev = to_pci_dev(xe->drm.dev); u32 value = xe_mmio_read32(xe_root_tile_mmio(xe), VF_CAP_REG); + /* + * If the device is inaccessible (e.g. parent bridge stuck in D3cold, + * fatal AER Errors) MMIO reads returns all-ones, 0xffff. + * VF_CAP would appear set and would misdetect as VF mode. + * Sanity check PCI presence before trusting the read. + */ + if (value == U32_MAX && !pci_device_is_present(pdev)) { + drm_err(&xe->drm, + "VF_CAP_REG returned all 1s, config space looks to be dead, skipping SR-IOV mode detection\n"); + return false; + } + return value & VF_CAP; } -- 2.25.1