From: Seth Forshee seth.forshee@canonical.com
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@canonical.com Signed-off-by: Dave Airlie airlied@gmail.com Signed-off-by: Lukas Wunner lukas@wunner.de --- drivers/gpu/drm/drm_edid.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+)
diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c index 53bc7a6..f208bb3 100644 --- a/drivers/gpu/drm/drm_edid.c +++ b/drivers/gpu/drm/drm_edid.c @@ -32,6 +32,7 @@ #include <linux/hdmi.h> #include <linux/i2c.h> #include <linux/module.h> +#include <linux/vga_switcheroo.h> #include <drm/drmP.h> #include <drm/drm_edid.h> #include <drm/drm_displayid.h> @@ -87,6 +88,8 @@ 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; @@ -1325,6 +1328,16 @@ struct edid *drm_get_edid(struct drm_connector *connector, struct i2c_adapter *adapter) { struct edid *edid; + 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)) return NULL; @@ -1332,6 +1345,11 @@ struct edid *drm_get_edid(struct drm_connector *connector, edid = drm_do_get_edid(connector, drm_do_probe_ddc_edid, adapter); if (edid) drm_get_displayid(connector, edid); + + if (active_pdev && active_pdev != pdev) + vga_switcheroo_switch_ddc(active_pdev); + + mutex_unlock(&drm_edid_mutex); return edid; } EXPORT_SYMBOL(drm_get_edid);