Unlock DDC lines if drm_probe_ddc() fails.
intel_dp_detect_dpcd() calls drm_probe_ddc(), needs to lock DDC
lines.
Don't lock vgasr_mutex in vga_switcheroo_lock/unlock_ddc(), it's
already locked in vga_switcheroo_debugfs_write(), leading to a
deadlock upon reprobe in stage2 when the new client reads the EDID.
Locking ddc_lock is sufficient.
If the inactive client registers before the active client then
old_ddc_owner cannot be determined with find_active_client()
(null pointer dereference). Therefore change semantics of the
switch_ddc() handler callback to return old_ddc_owner on success
or a negative int on failure.
Lock ddc_lock in stage2 to avoid race condition where reading the
EDID and switching happens simultaneously.
Switch DDC lines on MIGD / MDIS commands and on runtime suspend.
Signed-off-by: Lukas Wunner <lukas@xxxxxxxxx>
---
drivers/gpu/drm/drm_edid.c | 4 +-
drivers/gpu/drm/i915/intel_dp.c | 6 ++-
drivers/gpu/vga/vga_switcheroo.c | 82 ++++++++++++++++++++++-----------------
drivers/platform/x86/apple-gmux.c | 15 ++++++-
include/linux/vga_switcheroo.h | 3 +-
5 files changed, 71 insertions(+), 39 deletions(-)
diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index f91593b..8950722 100644
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -1329,8 +1329,10 @@ struct edid *drm_get_edid(struct drm_connector *connector,
vga_switcheroo_lock_ddc(connector->dev->pdev);
- if (!drm_probe_ddc(adapter))
+ if (!drm_probe_ddc(adapter)) {
+ vga_switcheroo_unlock_ddc(connector->dev->pdev);
return NULL;
+ }
edid = drm_do_get_edid(connector, drm_do_probe_ddc_edid, adapter);
if (edid)
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index d023710..e9c40b1 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -30,6 +30,7 @@
#include <linux/export.h>
#include <linux/notifier.h>
#include <linux/reboot.h>
+#include <linux/vga_switcheroo.h>
#include <drm/drmP.h>
#include <drm/drm_atomic_helper.h>
#include <drm/drm_crtc.h>
@@ -4079,6 +4080,7 @@ intel_dp_detect_dpcd(struct intel_dp *intel_dp)
{
uint8_t *dpcd = intel_dp->dpcd;
uint8_t type;
+ struct pci_dev *pdev = intel_dp->attached_connector->base.dev->pdev;
if (!intel_dp_get_dpcd(intel_dp))
return connector_status_disconnected;
@@ -4101,7 +4103,9 @@ intel_dp_detect_dpcd(struct intel_dp *intel_dp)
}
/* If no HPD, poke DDC gently */
- if (drm_probe_ddc(&intel_dp->aux.ddc))
+ if (vga_switcheroo_lock_ddc(pdev) >= 0 &&
+ drm_probe_ddc(&intel_dp->aux.ddc) &&
+ vga_switcheroo_unlock_ddc(pdev) >= 0)
return connector_status_connected;
/* Well we tried, say unknown for unreliable port types */
diff --git a/drivers/gpu/vga/vga_switcheroo.c b/drivers/gpu/vga/vga_switcheroo.c
index 0223020..2534d84 100644
--- a/drivers/gpu/vga/vga_switcheroo.c
+++ b/drivers/gpu/vga/vga_switcheroo.c
@@ -9,12 +9,13 @@
Switcher interface - methods require for ATPX and DCM
- switchto - this throws the output MUX switch
- - discrete_set_power - sets the power state for the discrete card
+ - switch_ddc - switch only DDC lines, return old DDC owner (or < 0 on failure)
+ - power_state - sets the power state for either GPU
GPU driver interface
- set_gpu_state - this should do the equiv of s/r for the card
- this should *not* set the discrete power state
- - switch_check - check if the device is in a position to switch now
+ - can_switch - check if the device is in a position to switch now
*/
#include <linux/module.h>
@@ -59,7 +60,7 @@ struct vgasr_priv {
struct vga_switcheroo_handler *handler;
struct mutex ddc_lock;
- struct pci_dev *old_ddc_owner;
+ enum vga_switcheroo_client_id old_ddc_owner;
};
#define ID_BIT_AUDIO 0x100
@@ -276,12 +277,9 @@ EXPORT_SYMBOL(vga_switcheroo_client_fb_set);
int vga_switcheroo_lock_ddc(struct pci_dev *pdev)
{
- struct vga_switcheroo_client *client;
int ret = 0;
int id;
- mutex_lock(&vgasr_mutex);
-
if (!vgasr_priv.handler) {
ret = -ENODEV;
goto out;
@@ -290,22 +288,17 @@ int vga_switcheroo_lock_ddc(struct pci_dev *pdev)
if (vgasr_priv.handler->switch_ddc) {
mutex_lock(&vgasr_priv.ddc_lock);
- client = find_active_client(&vgasr_priv.clients);
- if (!client) {
- mutex_unlock(&vgasr_priv.ddc_lock);
- ret = -ENODEV;
- goto out;
- }
- vgasr_priv.old_ddc_owner = client->pdev;
- if (client->pdev == pdev)
- goto out;
-
id = vgasr_priv.handler->get_client_id(pdev);
ret = vgasr_priv.handler->switch_ddc(id);
+
+ if (ret < 0) {
+ mutex_unlock(&vgasr_priv.ddc_lock);
+ printk(KERN_ERR "vga_switcheroo: failed to switch DDC lines\n");
+ } else
+ vgasr_priv.old_ddc_owner = ret;
}
out:
- mutex_unlock(&vgasr_mutex);
return ret;
}
EXPORT_SYMBOL(vga_switcheroo_lock_ddc);
@@ -314,7 +307,6 @@ int vga_switcheroo_unlock_ddc(struct pci_dev *pdev)
{
int ret = 0;
int id;
- mutex_lock(&vgasr_mutex);
if (!vgasr_priv.handler) {
ret = -ENODEV;
@@ -322,15 +314,17 @@ int vga_switcheroo_unlock_ddc(struct pci_dev *pdev)
}
if (vgasr_priv.handler->switch_ddc) {
- if (vgasr_priv.old_ddc_owner != pdev) {
- id = vgasr_priv.handler->get_client_id(vgasr_priv.old_ddc_owner);
- ret = vgasr_priv.handler->switch_ddc(id);
- }
- vgasr_priv.old_ddc_owner = NULL;
+ id = vgasr_priv.handler->get_client_id(pdev);
+
+ if (vgasr_priv.old_ddc_owner != id)
+ ret = vgasr_priv.handler->switch_ddc(vgasr_priv.old_ddc_owner);
+ if (ret < 0)
+ printk(KERN_ERR "vga_switcheroo: failed to switch DDC lines\n");
+
mutex_unlock(&vgasr_priv.ddc_lock);
}
+
out:
- mutex_unlock(&vgasr_mutex);
return ret;
}
EXPORT_SYMBOL(vga_switcheroo_unlock_ddc);
@@ -433,14 +427,24 @@ static int vga_switchto_stage2(struct vga_switcheroo_client *new_client)
}
if (vgasr_priv.handler->switch_ddc) {
+ mutex_lock(&vgasr_priv.ddc_lock);
ret = vgasr_priv.handler->switch_ddc(new_client->id);
- if (ret)
+ mutex_unlock(&vgasr_priv.ddc_lock);
+ if (ret < 0) {
+ printk(KERN_ERR "vga_switcheroo: failed to switch DDC lines\n");
return ret;
+ }
}
ret = vgasr_priv.handler->switchto(new_client->id);
- if (ret)
- goto restore_ddc;
+ if (ret) {
+ printk(KERN_ERR "vga_switcheroo: failed to switch to client %d\n", new_client->id);
+ /* restore DDC lines */
+ mutex_lock(&vgasr_priv.ddc_lock);
+ vgasr_priv.handler->switch_ddc(active->id);
+ mutex_unlock(&vgasr_priv.ddc_lock);
+ return ret;
+ }
if (new_client->ops->reprobe)
new_client->ops->reprobe(new_client->pdev);
@@ -452,14 +456,6 @@ static int vga_switchto_stage2(struct vga_switcheroo_client *new_client)
new_client->active = true;
return 0;
-
-restore_ddc:
- if (vgasr_priv.handler->switch_ddc) {
- int id = (new_client->id == VGA_SWITCHEROO_IGD) ?
- VGA_SWITCHEROO_DIS : VGA_SWITCHEROO_IGD;
- ret = vgasr_priv.handler->switch_ddc(id);
- }
- return ret;
}
static bool check_can_switch(void)
@@ -561,6 +557,15 @@ vga_switcheroo_debugfs_write(struct file *filp, const char __user *ubuf,
vgasr_priv.delayed_switch_active = false;
if (just_mux) {
+ if (vgasr_priv.handler->switch_ddc) {
+ mutex_lock(&vgasr_priv.ddc_lock);
+ ret = vgasr_priv.handler->switch_ddc(client_id);
+ mutex_unlock(&vgasr_priv.ddc_lock);
+ if (ret < 0) {
+ printk(KERN_ERR "vga_switcheroo: failed to switch DDC lines\n");
+ goto out;
+ }
+ }
ret = vgasr_priv.handler->switchto(client_id);
goto out;
}
@@ -716,6 +721,13 @@ static int vga_switcheroo_runtime_suspend(struct device *dev)
ret = dev->bus->pm->runtime_suspend(dev);
if (ret)
return ret;
+ if (vgasr_priv.handler->switch_ddc) {
+ mutex_lock(&vgasr_priv.ddc_lock);
+ ret = vgasr_priv.handler->switch_ddc(VGA_SWITCHEROO_IGD);
+ mutex_unlock(&vgasr_priv.ddc_lock);
+ if (ret < 0)
+ printk(KERN_ERR "vga_switcheroo: failed to switch DDC lines\n");
+ }
if (vgasr_priv.handler->switchto)
vgasr_priv.handler->switchto(VGA_SWITCHEROO_IGD);
vga_switcheroo_power_switch(pdev, VGA_SWITCHEROO_OFF);
diff --git a/drivers/platform/x86/apple-gmux.c b/drivers/platform/x86/apple-gmux.c
index 1cf242c..9aafbde 100644
--- a/drivers/platform/x86/apple-gmux.c
+++ b/drivers/platform/x86/apple-gmux.c
@@ -273,11 +273,24 @@ static const struct backlight_ops gmux_bl_ops = {
static int gmux_switch_ddc(enum vga_switcheroo_client_id id)
{
+ enum vga_switcheroo_client_id old_ddc_owner;
+
+ if (gmux_read8(apple_gmux_data, GMUX_PORT_SWITCH_DDC) == 1)
+ old_ddc_owner = VGA_SWITCHEROO_IGD;
+ else
+ old_ddc_owner = VGA_SWITCHEROO_DIS;
+
+ pr_debug("Switching gmux DDC from %d to %d\n", old_ddc_owner, id);
+
+ if (id == old_ddc_owner)
+ return old_ddc_owner;
+
if (id == VGA_SWITCHEROO_IGD)
gmux_write8(apple_gmux_data, GMUX_PORT_SWITCH_DDC, 1);
else
gmux_write8(apple_gmux_data, GMUX_PORT_SWITCH_DDC, 2);
- return 0;
+
+ return old_ddc_owner;
}
static int gmux_switchto(enum vga_switcheroo_client_id id)
diff --git a/include/linux/vga_switcheroo.h b/include/linux/vga_switcheroo.h
index 352bef3..8963799 100644
--- a/include/linux/vga_switcheroo.h
+++ b/include/linux/vga_switcheroo.h
@@ -77,7 +77,8 @@ static inline void vga_switcheroo_unregister_client(struct pci_dev *dev) {}
static inline int vga_switcheroo_register_client(struct pci_dev *dev,
const struct vga_switcheroo_client_ops *ops, bool driver_power_control) { return 0; }
static inline void vga_switcheroo_client_fb_set(struct pci_dev *dev, struct fb_info *info) {}
-static inline void vga_switcheroo_switch_ddc(struct pci_dev *pdev) { return NULL; }
+static inline int vga_switcheroo_lock_ddc(struct pci_dev *pdev) { return 0; }
+static inline int vga_switcheroo_unlock_ddc(struct pci_dev *pdev) { return 0; }
static inline int vga_switcheroo_register_handler(struct vga_switcheroo_handler *handler) { return 0; }
static inline int vga_switcheroo_register_audio_client(struct pci_dev *pdev,
const struct vga_switcheroo_client_ops *ops,
--
1.8.5.2 (Apple Git-48)
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