From patchwork Wed Nov 20 23:46:08 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lucas De Marchi X-Patchwork-Id: 11255027 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id E1D401390 for ; Thu, 21 Nov 2019 00:21:10 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id C9ADC20878 for ; Thu, 21 Nov 2019 00:21:10 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C9ADC20878 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=intel-gfx-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 3DC996EA9D; Thu, 21 Nov 2019 00:21:09 +0000 (UTC) X-Original-To: intel-gfx@lists.freedesktop.org Delivered-To: intel-gfx@lists.freedesktop.org Received: from mga04.intel.com (mga04.intel.com [192.55.52.120]) by gabe.freedesktop.org (Postfix) with ESMTPS id 143B66EA9D for ; Thu, 21 Nov 2019 00:21:08 +0000 (UTC) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga104.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 20 Nov 2019 16:21:08 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.69,223,1571727600"; d="scan'208";a="215979115" Received: from ldmartin1-desk.jf.intel.com ([10.54.74.64]) by fmsmga001.fm.intel.com with ESMTP; 20 Nov 2019 16:21:07 -0800 From: Lucas De Marchi To: intel-gfx@lists.freedesktop.org Date: Wed, 20 Nov 2019 15:46:08 -0800 Message-Id: <20191120234608.17775-3-lucas.demarchi@intel.com> X-Mailer: git-send-email 2.24.0 In-Reply-To: <20191120234608.17775-1-lucas.demarchi@intel.com> References: <20191120234608.17775-1-lucas.demarchi@intel.com> MIME-Version: 1.0 Subject: [Intel-gfx] [PATCH 3/3] drm/i915/i915: assume vbt is 4-byte aligned into oprom X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" The unaligned ioread32() will make us read byte by byte looking for the vbt. We could just as well have done a ioread8() + a shift and avoid the extra confusion on how we are looking for "$VBT". However when using ACPI it's guaranteed the VBT is 4-byte aligned per spec, so we can probably assume it here as well. Signed-off-by: Lucas De Marchi --- drivers/gpu/drm/i915/display/intel_bios.c | 19 ++++++------------- 1 file changed, 6 insertions(+), 13 deletions(-) diff --git a/drivers/gpu/drm/i915/display/intel_bios.c b/drivers/gpu/drm/i915/display/intel_bios.c index aa9b182efee5..6bf57b1ad056 100644 --- a/drivers/gpu/drm/i915/display/intel_bios.c +++ b/drivers/gpu/drm/i915/display/intel_bios.c @@ -1902,27 +1902,20 @@ static struct vbt_header *oprom_get_vbt(struct drm_i915_private *dev_priv) void __iomem *p = NULL, *oprom; struct vbt_header *vbt; u16 vbt_size; - size_t i, size; + size_t size; oprom = pci_map_rom(pdev, &size); if (!oprom) return NULL; /* Scour memory looking for the VBT signature. */ - for (i = 0; i + 4 < size; i++) { - if (ioread32(oprom + i) != *((const u32 *)"$VBT")) - continue; - - p = oprom + i; - size -= i; - break; - } - - if (!p) - goto err_unmap_oprom; + for (p = oprom; size >= 4; p += 4, size -= 4) + if (ioread32(p) == *((const u32 *)"$VBT")) + break; if (sizeof(struct vbt_header) > size) { - DRM_DEBUG_DRIVER("VBT header incomplete\n"); + if (size >= 4) + DRM_DEBUG_DRIVER("VBT header incomplete\n"); goto err_unmap_oprom; }