linux-kernel - Re: radeon vs radeonfb Mobility quirks (Thinkpad X32)

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Date:   Thu, 08 Nov 2018 13:19:17 +1100
From:   Benjamin Herrenschmidt <benh@...nel.crashing.org>
To:     Eric Wong <e@...24.org>
Cc:     David Airlie <airlied@...ux.ie>,
        Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>,
        linux-fbdev@...r.kernel.org, dri-devel@...ts.freedesktop.org,
        linux-kernel@...r.kernel.org, amd-gfx@...ts.freedesktop.org,
        Alex Deucher <alexander.deucher@....com>,
        Christian König <christian.koenig@....com>,
        "David (ChunMing) Zhou" <David1.Zhou@....com>
Subject: Re: radeon vs radeonfb Mobility quirks (Thinkpad X32)

On Thu, 2018-11-08 at 00:03 +0000, Eric Wong wrote:
> Benjamin Herrenschmidt <benh@...nel.crashing.org> wrote:
> > There's a whole pile of power management stuff for ancient laptops that
> > never quite made it from radeonfb to the radeon DRM driver... sadly it
> > also prevents sleep on old PowerBooks but I haven't had many complaints
> > so...
> 
> Thanks for the confirmation that stuff is missing from the DRM driver.
> 
> > The code for D2 and D3 on those old things is reasonably self
> > contained, it shouldn't be that hard to move it over I suppose.
> 
> I started working on the following (dirty) patch for my X32,
> but hasn't made a difference with just PCI_D2:

Yes, as you noticed below, you need the rest of the stuff. If you stick
to D2 and avoid the Mac "D3 cold" stuff, it's easier. You also need to
look at some of the dynamic clock stuff.

Cheers,
Ben.

> diff --git a/drivers/gpu/drm/radeon/radeon_device.c b/drivers/gpu/drm/radeon/radeon_device.c
> index 59c8a6647ff2..acc587b18ad2 100644
> --- a/drivers/gpu/drm/radeon/radeon_device.c
> +++ b/drivers/gpu/drm/radeon/radeon_device.c
> @@ -1548,6 +1548,23 @@ void radeon_device_fini(struct radeon_device *rdev)
>  		radeon_doorbell_fini(rdev);
>  }
>  
> +/* XXX copy of radeonfb_whack_power_state */
> +static void radeon_whack_power_state(struct pci_dev *pdev, pci_power_t state)
> +{
> +	u16 pwr_cmd;
> +
> +	for (;;) {
> +		pci_read_config_word(pdev, pdev->pm_cap + PCI_PM_CTRL,
> +				     &pwr_cmd);
> +		if (pwr_cmd & state)
> +			break;
> +		pwr_cmd = (pwr_cmd & ~PCI_PM_CTRL_STATE_MASK) | state;
> +		pci_write_config_word(pdev, pdev->pm_cap + PCI_PM_CTRL,
> +				      pwr_cmd);
> +		msleep(500);
> +	}
> +	pdev->current_state = state;
> +}
>  
>  /*
>   * Suspend & resume.
> @@ -1596,6 +1613,7 @@ int radeon_suspend_kms(struct drm_device *dev, bool suspend,
>  
>  		if (radeon_crtc->cursor_bo) {
>  			struct radeon_bo *robj = gem_to_radeon_bo(radeon_crtc->cursor_bo);
> +
>  			r = radeon_bo_reserve(robj, false);
>  			if (r == 0) {
>  				radeon_bo_unpin(robj);
> @@ -1647,7 +1665,13 @@ int radeon_suspend_kms(struct drm_device *dev, bool suspend,
>  	} else if (suspend) {
>  		/* Shut down the device */
>  		pci_disable_device(dev->pdev);
> -		pci_set_power_state(dev->pdev, PCI_D3hot);
> +
> +		if ("X32") {
> +			radeon_whack_power_state(dev->pdev, PCI_D2);
> +			__pci_complete_power_transition(dev->pdev, PCI_D2);
> +		} else {
> +			pci_set_power_state(dev->pdev, PCI_D3hot);
> +		}
>  	}
>  
>  	if (fbcon) {
> 
> 
> I suppose some of the mobility stuff from
> drivers/video/fbdev/aty/radeon_pm.c is necessary, but I haven't
> figured it out for the DRM driver.  Not sure when/if I'll have
> time to figure it out, or if I'll stick to the radeonfb driver
> for now.
> 
> 		/* Prepare mobility chips for suspend.
> 		 */
> 		if (rinfo->is_mobility) {
> 			/* Program V2CLK */
> 			radeon_pm_program_v2clk(rinfo);
> 		
> 			/* Disable IO PADs */
> 			radeon_pm_disable_iopad(rinfo);
> 
> 			/* Set low current */
> 			radeon_pm_low_current(rinfo);
> 
> 			/* Prepare chip for power management */
> 			radeon_pm_setup_for_suspend(rinfo);