[PATCH 1/7] vga_switcheroo: Add support for switching only the DDC

From: Seth Forshee
Date: Fri Sep 07 2012 - 11:23:28 EST


During graphics driver initialization its useful to be able to mux only
the DDC to the inactive client in order to read the EDID. Add a
switch_ddc callback to allow capable handlers to provide this
functionality, and add vga_switcheroo_switch_ddc() to allow DRM to mux
only the DDC.

Signed-off-by: Seth Forshee <seth.forshee@xxxxxxxxxxxxx>
---
drivers/gpu/vga/vga_switcheroo.c | 39 +++++++++++++++++++++++++++++++++++++-
include/linux/vga_switcheroo.h | 4 ++++
2 files changed, 42 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/vga/vga_switcheroo.c b/drivers/gpu/vga/vga_switcheroo.c
index e25cf31..ea6bcc2 100644
--- a/drivers/gpu/vga/vga_switcheroo.c
+++ b/drivers/gpu/vga/vga_switcheroo.c
@@ -252,6 +252,29 @@ void vga_switcheroo_client_fb_set(struct pci_dev *pdev,
}
EXPORT_SYMBOL(vga_switcheroo_client_fb_set);

+int vga_switcheroo_switch_ddc(struct pci_dev *pdev)
+{
+ int ret = 0;
+ int id;
+
+ mutex_lock(&vgasr_mutex);
+
+ if (!vgasr_priv.handler) {
+ ret = -ENODEV;
+ goto out;
+ }
+
+ if (vgasr_priv.handler->switch_ddc) {
+ id = vgasr_priv.handler->get_client_id(pdev);
+ ret = vgasr_priv.handler->switch_ddc(id);
+ }
+
+out:
+ mutex_unlock(&vgasr_mutex);
+ return ret;
+}
+EXPORT_SYMBOL(vga_switcheroo_switch_ddc);
+
static int vga_switcheroo_show(struct seq_file *m, void *v)
{
struct vga_switcheroo_client *client;
@@ -342,9 +365,15 @@ static int vga_switchto_stage2(struct vga_switcheroo_client *new_client)
fb_notifier_call_chain(FB_EVENT_REMAP_ALL_CONSOLE, &event);
}

+ if (vgasr_priv.handler->switch_ddc) {
+ ret = vgasr_priv.handler->switch_ddc(new_client->id);
+ if (ret)
+ return ret;
+ }
+
ret = vgasr_priv.handler->switchto(new_client->id);
if (ret)
- return ret;
+ goto restore_ddc;

if (new_client->ops->reprobe)
new_client->ops->reprobe(new_client->pdev);
@@ -356,6 +385,14 @@ 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)
diff --git a/include/linux/vga_switcheroo.h b/include/linux/vga_switcheroo.h
index ddb419c..b0d0839 100644
--- a/include/linux/vga_switcheroo.h
+++ b/include/linux/vga_switcheroo.h
@@ -29,6 +29,7 @@ enum vga_switcheroo_client_id {
};

struct vga_switcheroo_handler {
+ int (*switch_ddc)(enum vga_switcheroo_client_id id);
int (*switchto)(enum vga_switcheroo_client_id id);
int (*power_state)(enum vga_switcheroo_client_id id,
enum vga_switcheroo_state state);
@@ -53,6 +54,8 @@ int vga_switcheroo_register_audio_client(struct pci_dev *pdev,
void vga_switcheroo_client_fb_set(struct pci_dev *dev,
struct fb_info *info);

+int vga_switcheroo_switch_ddc(struct pci_dev *pdev);
+
int vga_switcheroo_register_handler(struct vga_switcheroo_handler *handler);
void vga_switcheroo_unregister_handler(void);

@@ -66,6 +69,7 @@ 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) { 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_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,
--
1.7.9.5

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