Re: [PATCH] Restore mux and power states after resume from hibernation

[Jani Nikula <jani.nikula@linux.intel.com>]

On Mon, 28 Oct 2013, Stefan Demharter <stefan.demharter@gmx.net> wrote:
> Hi all,
>
> i've got a system with a muxed intel+ati card and had a problem with hibernation:
> Vgaswitcheroo didn't restore the states of the graphics cards and the state of the mux after resume.
>
> I have solved the issue with the attached patch.
>
> Can you please review it?

I see that Daniel asked for the patch to be sent here in [1]. Thanks,
and sorry that it's been neglected!

I did not look at the patch either (not really my area of expertise) but
please consider sending the patch in proper patch format (with
Signed-off-by, see Documentation/SubmittingPatches), and do pay
attention to Documentation/CodingStyle (at least wrt comments and having
a newline after if (cond)). This might help you get the review.

Thanks,
Jani.


[1] https://bugs.freedesktop.org/show_bug.cgi?id=70863



>
> Regards
> Stefan
> commit cd8f863a804d9388b09771640110577dddafc695
> Author: Stefan Demharter <stefan.demharter@gmx.net>
> Date:   Thu Oct 24 00:06:09 2013 +0200
>
>     vgaswitcheroo: restore mux and power states after resume from hibernation.
>
> diff --git a/drivers/gpu/vga/vga_switcheroo.c b/drivers/gpu/vga/vga_switcheroo.c
> index ec0ae2d..4731f02 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 +73,46 @@ static struct vgasr_priv vgasr_priv = {
>  	.clients = LIST_HEAD_INIT(vgasr_priv.clients),
>  };
>  
> +/* save state of mux to restore it upon hibernation resume */
> +// Assume initial state after boot: mux is set to IGD
> +#define MUX_POWER_ON_STATE VGA_SWITCHEROO_IGD
> +static int mux_id = MUX_POWER_ON_STATE;
> +
> +static int vga_switchoff(struct vga_switcheroo_client *client);
> +
> +static int vga_resume(struct notifier_block *nb,
> +                                unsigned long val, void *ign)
> +{
> +	int ret = 0;
> +	struct vga_switcheroo_client *client;
> +	pr_info("vga_switcheroo: vga_resume %d %d %d\n", (int)val, PM_POST_HIBERNATION, mux_id);
> +	if (val != PM_POST_HIBERNATION) return 0;
> +	if (mux_id != VGA_SWITCHEROO_IGD) {
> +		mutex_lock(&vgasr_mutex);
> +		pr_info("vga_switcheroo: restoring switch to %d after hibernate\n", mux_id);
> +		// Restore mux state
> +		if (mux_id != MUX_POWER_ON_STATE)
> +			ret = vgasr_priv.handler->switchto(mux_id);
> +		// Restore power state
> +		// Assumes all gpus have power after boot
> +		list_for_each_entry(client, &vgasr_priv.clients, list) {
> +			if (!client->pwr_state) {
> +				// Device was powered off, so we redo that...
> +				pr_info("vga_switcheroo: restoring power off of device %d after hibernate\n", client->id);
> +				vga_switchoff(client);
> +			}
> +		}
> +		mutex_unlock(&vgasr_mutex);
> +		if (ret) pr_warn("vga_switcheroo: failed\n");
> +	}
> +	return 0;
> +}
> +
> +static struct notifier_block vga_pm_nb = {
> +	.notifier_call = vga_resume,
> +	.priority = 0,
> +};
> +
>  static bool vga_switcheroo_ready(void)
>  {
>  	/* we're ready if we get two clients + handler */
> @@ -83,6 +124,7 @@ static void vga_switcheroo_enable(void)
>  {
>  	int ret;
>  	struct vga_switcheroo_client *client;
> +	register_pm_notifier(&vga_pm_nb);
>  
>  	/* call the handler to init */
>  	if (vgasr_priv.handler->init)
> @@ -119,14 +161,21 @@ int vga_switcheroo_register_handler(struct vga_switcheroo_handler *handler)
>  }
>  EXPORT_SYMBOL(vga_switcheroo_register_handler);
>  
> +// vgasr_mutex has to be locked from caller
> +void vga_switcheroo_disable(void)
> +{
> +	unregister_pm_notifier(&vga_pm_nb);
> +	pr_info("vga_switcheroo: disabled\n");
> +	vga_switcheroo_debugfs_fini(&vgasr_priv);
> +	vgasr_priv.active = false;
> +}
> +
>  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);
>  }
> @@ -235,9 +284,7 @@ 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);
>  }
> @@ -262,12 +309,13 @@ 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->driver_power_control ? "Dyn" : "",
>  			   client->pwr_state ? "Pwr" : "Off",
> +			   client_id(client) == mux_id ? "mux" : "",
>  			   pci_name(client->pdev));
>  		i++;
>  	}
> @@ -304,6 +352,15 @@ static int vga_switchoff(struct vga_switcheroo_client *client)
>  	return 0;
>  }
>  
> +static int vga_switch_mux_to(int client_id)
> +{
> +	int ret = vgasr_priv.handler->switchto(client_id);
> +	if (ret == 0) {
> +		mux_id = client_id;
> +	}
> +	return ret;
> +}
> +
>  static void set_audio_state(int id, int state)
>  {
>  	struct vga_switcheroo_client *client;
> @@ -353,7 +410,7 @@ static int vga_switchto_stage2(struct vga_switcheroo_client *new_client)
>  		console_unlock();
>  	}
>  
> -	ret = vgasr_priv.handler->switchto(new_client->id);
> +	ret = vga_switch_mux_to(new_client->id);
>  	if (ret)
>  		return ret;
>  
> @@ -468,7 +525,7 @@ 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_switch_mux_to(client_id);
>  		goto out;
>  	}
>  
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-- 
Jani Nikula, Intel Open Source Technology Center