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 at canonical.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 a8743c3..1a4b661 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;
@@ -395,12 +398,26 @@ 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
