[PATCH RFC v2] vga_switcheroo: restore mux and power states upon resume from hibernation.
Alex Deucher
alexdeucher at gmail.com
Fri Jan 31 06:32:46 PST 2014
On Thu, Jan 30, 2014 at 6:46 PM, Stefan Demharter
<stefan.demharter at gmx.net> wrote:
> Saves the current state of the mux and restores it upon resume from hibernation.
> This is needed for muxed systems because the state of the mux doesn't survive a
> hibernation-resume cycle. Furthermore also restores the power state of a GPU
> to OFF after resume from hibernation if it was OFF before hibernation.
>
> Signed-off-by: Stefan Demharter <stefan.demharter at gmx.net>
Reviewed-by: Alex Deucher <alexander.deucher at amd.com>
> ---
> drivers/gpu/vga/vga_switcheroo.c | 96 +++++++++++++++++++++++++++++++++++-----
> 1 file changed, 85 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/gpu/vga/vga_switcheroo.c b/drivers/gpu/vga/vga_switcheroo.c
> index ec0ae2d..85f41b9 100644
> --- a/drivers/gpu/vga/vga_switcheroo.c
> +++ b/drivers/gpu/vga/vga_switcheroo.c
> @@ -28,6 +28,7 @@
> #include <linux/console.h>
> #include <linux/vga_switcheroo.h>
> #include <linux/pm_runtime.h>
> +#include <linux/suspend.h>
>
> #include <linux/vgaarb.h>
>
> @@ -72,6 +73,64 @@ static struct vgasr_priv vgasr_priv = {
> .clients = LIST_HEAD_INIT(vgasr_priv.clients),
> };
>
> +#define MUX_STATE_UNDEFINED (-1)
> +/*
> + * The next variable stores the state of the mux
> + * so it can be restored upon resume from hibernation.
> + */
> +static int mux_state = MUX_STATE_UNDEFINED;
> +
> +static void vga_restore_mux(void)
> +{
> + if (mux_state != MUX_STATE_UNDEFINED) {
> + int ret;
> + pr_info("vga_switcheroo: restoring mux state to %s\n",
> + mux_state == VGA_SWITCHEROO_IGD ? "IGD" : "DIS");
> +
> + ret = vgasr_priv.handler->switchto(mux_state);
> + if (ret)
> + pr_warn("vga_switcheroo: mux switch failed (%d)\n", ret);
> + }
> +}
> +
> +static void vga_restore_power_state(void)
> +{
> + struct vga_switcheroo_client *client;
> +
> + if (!vgasr_priv.handler->power_state)
> + return;
> +
> + list_for_each_entry(client, &vgasr_priv.clients, list) {
> + if (client_is_vga(client) && client->pwr_state == VGA_SWITCHEROO_OFF) {
> + pr_info("vga_switcheroo: setting power state of %s to OFF\n",
> + client->id == VGA_SWITCHEROO_IGD ? "IGD" : "DIS");
> + vgasr_priv.handler->power_state(client->id, client->pwr_state);
> + }
> + }
> +}
> +
> +/*
> + * Handle resume from hibernation:
> + * Restore mux state and power states for switcheroo controlled GPUs.
> + */
> +static int vga_resume(struct notifier_block *nb, unsigned long action, void *unused)
> +{
> + switch (action) {
> + case PM_POST_HIBERNATION:
> + mutex_lock(&vgasr_mutex);
> + vga_restore_mux();
> + vga_restore_power_state();
> + mutex_unlock(&vgasr_mutex);
> + break;
> + }
> + return 0;
> +}
> +
> +static struct notifier_block vga_switcheroo_pm_nb = {
> + .notifier_call = vga_resume,
> + .priority = 0,
> +};
> +
> static bool vga_switcheroo_ready(void)
> {
> /* we're ready if we get two clients + handler */
> @@ -84,6 +143,8 @@ static void vga_switcheroo_enable(void)
> int ret;
> struct vga_switcheroo_client *client;
>
> + pr_info("vga_switcheroo: enabled\n");
> +
> /* call the handler to init */
> if (vgasr_priv.handler->init)
> vgasr_priv.handler->init();
> @@ -99,6 +160,15 @@ static void vga_switcheroo_enable(void)
> }
> vga_switcheroo_debugfs_init(&vgasr_priv);
> vgasr_priv.active = true;
> + register_pm_notifier(&vga_switcheroo_pm_nb);
> +}
> +
> +void vga_switcheroo_disable(void)
> +{
> + unregister_pm_notifier(&vga_switcheroo_pm_nb);
> + vgasr_priv.active = false;
> + vga_switcheroo_debugfs_fini(&vgasr_priv);
> + pr_info("vga_switcheroo: disabled\n");
> }
>
> int vga_switcheroo_register_handler(struct vga_switcheroo_handler *handler)
> @@ -111,7 +181,6 @@ int vga_switcheroo_register_handler(struct vga_switcheroo_handler *handler)
>
> vgasr_priv.handler = handler;
> if (vga_switcheroo_ready()) {
> - printk(KERN_INFO "vga_switcheroo: enabled\n");
> vga_switcheroo_enable();
> }
> mutex_unlock(&vgasr_mutex);
> @@ -124,9 +193,7 @@ void vga_switcheroo_unregister_handler(void)
> mutex_lock(&vgasr_mutex);
> vgasr_priv.handler = NULL;
> if (vgasr_priv.active) {
> - pr_info("vga_switcheroo: disabled\n");
> - vga_switcheroo_debugfs_fini(&vgasr_priv);
> - vgasr_priv.active = false;
> + vga_switcheroo_disable();
> }
> mutex_unlock(&vgasr_mutex);
> }
> @@ -155,7 +222,6 @@ static int register_client(struct pci_dev *pdev,
> vgasr_priv.registered_clients++;
>
> if (vga_switcheroo_ready()) {
> - printk(KERN_INFO "vga_switcheroo: enabled\n");
> vga_switcheroo_enable();
> }
> mutex_unlock(&vgasr_mutex);
> @@ -235,9 +301,7 @@ void vga_switcheroo_unregister_client(struct pci_dev *pdev)
> kfree(client);
> }
> if (vgasr_priv.active && vgasr_priv.registered_clients < 2) {
> - printk(KERN_INFO "vga_switcheroo: disabled\n");
> - vga_switcheroo_debugfs_fini(&vgasr_priv);
> - vgasr_priv.active = false;
> + vga_switcheroo_disable();
> }
> mutex_unlock(&vgasr_mutex);
> }
> @@ -262,10 +326,11 @@ static int vga_switcheroo_show(struct seq_file *m, void *v)
> int i = 0;
> mutex_lock(&vgasr_mutex);
> list_for_each_entry(client, &vgasr_priv.clients, list) {
> - seq_printf(m, "%d:%s%s:%c:%s%s:%s\n", i,
> + seq_printf(m, "%d:%s%s:%c%s:%s%s:%s\n", i,
> client_id(client) == VGA_SWITCHEROO_DIS ? "DIS" : "IGD",
> client_is_vga(client) ? "" : "-Audio",
> client->active ? '+' : ' ',
> + client_id(client) == mux_state ? "mux" : "",
> client->driver_power_control ? "Dyn" : "",
> client->pwr_state ? "Pwr" : "Off",
> pci_name(client->pdev));
> @@ -304,6 +369,15 @@ static int vga_switchoff(struct vga_switcheroo_client *client)
> return 0;
> }
>
> +static int vga_switchto(int client_id)
> +{
> + int ret = vgasr_priv.handler->switchto(client_id);
> +
> + if (ret == 0)
> + mux_state = client_id;
> + return ret;
> +}
> +
> static void set_audio_state(int id, int state)
> {
> struct vga_switcheroo_client *client;
> @@ -353,7 +427,7 @@ static int vga_switchto_stage2(struct vga_switcheroo_client *new_client)
> console_unlock();
> }
>
> - ret = vgasr_priv.handler->switchto(new_client->id);
> + ret = vga_switchto(new_client->id);
> if (ret)
> return ret;
>
> @@ -468,7 +542,7 @@ vga_switcheroo_debugfs_write(struct file *filp, const char __user *ubuf,
> vgasr_priv.delayed_switch_active = false;
>
> if (just_mux) {
> - ret = vgasr_priv.handler->switchto(client_id);
> + ret = vga_switchto(client_id);
> goto out;
> }
>
> --
> 1.8.5.3
>
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