linux-kernel - [PATCH 5/7] drm/edid: Switch DDC when reading the EDID

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <1347031330-19657-6-git-send-email-seth.forshee@canonical.com>
Date:	Fri,  7 Sep 2012 10:22:08 -0500
From:	Seth Forshee <seth.forshee@...onical.com>
To:	dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org
Cc:	David Airlie <airlied@...ux.ie>, Matthew Garrett <mjg@...hat.com>,
	Daniel Vetter <daniel.vetter@...ll.ch>,
	Andreas Heider <andreas@...tr.de>,
	Seth Forshee <seth.forshee@...onical.com>
Subject: [PATCH 5/7] drm/edid: Switch DDC when reading the EDID

Some dual graphics machines support muxing the DDC separately from the
display, so make use of this functionality when reading the EDID on the
inactive GPU. Also serialize drm_get_edid() with a mutex to avoid races
on the DDC mux state.

Signed-off-by: Seth Forshee <seth.forshee@...onical.com>
---
 drivers/gpu/drm/drm_edid.c |   17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index b7ee230..b389269 100644
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -31,6 +31,7 @@
 #include <linux/slab.h>
 #include <linux/i2c.h>
 #include <linux/module.h>
+#include <linux/vga_switcheroo.h>
 #include "drmP.h"
 #include "drm_edid.h"
 #include "drm_edid_modes.h"
@@ -82,6 +83,8 @@ struct detailed_mode_closure {
 #define LEVEL_GTF2	2
 #define LEVEL_CVT	3
 
+static DEFINE_MUTEX(drm_edid_mutex);
+
 static struct edid_quirk {
 	char vendor[4];
 	int product_id;
@@ -398,12 +401,26 @@ struct edid *drm_get_edid(struct drm_connector *connector,
 			  struct i2c_adapter *adapter)
 {
 	struct edid *edid = NULL;
+	struct pci_dev *pdev = connector->dev->pdev;
+	struct pci_dev *active_pdev = NULL;
+
+	mutex_lock(&drm_edid_mutex);
+
+	if (pdev) {
+		active_pdev = vga_switcheroo_get_active_client();
+		if (active_pdev != pdev)
+			vga_switcheroo_switch_ddc(pdev);
+	}
 
 	if (drm_probe_ddc(adapter))
 		edid = (struct edid *)drm_do_get_edid(connector, adapter);
 
+	if (active_pdev && active_pdev != pdev)
+		vga_switcheroo_switch_ddc(active_pdev);
+
 	connector->display_info.raw_edid = (char *)edid;
 
+	mutex_unlock(&drm_edid_mutex);
 	return edid;
 
 }
-- 
1.7.9.5

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/