[PATCH] drm/radeon: fix power state when port pm is unavailable (v2)

[Peter Wu]

On Wed, Nov 23, 2016 at 12:43:33PM -0500, Alex Deucher wrote:
> From: Peter Wu <peter at lekensteyn.nl>
> 
> When PCIe port PM is not enabled (system BIOS is pre-2015 or the
> pcie_port_pm=off parameter is set), legacy ATPX PM should still be
> marked as supported. Otherwise the GPU can fail to power on after
> runtime suspend. This affected a Dell Inspiron 5548.
> 
> Ideally the BIOS date in the PCI core is lowered to 2013 (the first year
> where hybrid graphics platforms using power resources was introduced),
> but that seems more risky at this point and would not solve the
> pcie_port_pm=off issue.
> 
> v2: agd: fix typo

Oops, silly copy/paste error from my side (accidentally replaced
is_hybrid instead of power_cntl). Good catch!

Peter

PS. mail server refused to accept mail due to '#' in Cc, need CC:
<stable at ...> # 4.8+ below.

> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=98505
> Signed-off-by: Peter Wu <peter at lekensteyn.nl>
> Signed-off-by: Alex Deucher <alexander.deucher at amd.com>
> Cc: stable at vger.kernel.org # 4.8
> Reviewed-by: Alex Deucher <alexander.deucher at amd.com>
> ---
>  drivers/gpu/drm/radeon/radeon_atpx_handler.c | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/radeon/radeon_atpx_handler.c b/drivers/gpu/drm/radeon/radeon_atpx_handler.c
> index 2fdcd04..4129b12 100644
> --- a/drivers/gpu/drm/radeon/radeon_atpx_handler.c
> +++ b/drivers/gpu/drm/radeon/radeon_atpx_handler.c
> @@ -34,6 +34,7 @@ struct radeon_atpx {
>  
>  static struct radeon_atpx_priv {
>  	bool atpx_detected;
> +	bool bridge_pm_usable;
>  	/* handle for device - and atpx */
>  	acpi_handle dhandle;
>  	struct radeon_atpx atpx;
> @@ -203,7 +204,11 @@ static int radeon_atpx_validate(struct radeon_atpx *atpx)
>  	atpx->is_hybrid = false;
>  	if (valid_bits & ATPX_MS_HYBRID_GFX_SUPPORTED) {
>  		printk("ATPX Hybrid Graphics\n");
> -		atpx->functions.power_cntl = false;
> +		/*
> +		 * Disable legacy PM methods only when pcie port PM is usable,
> +		 * otherwise the device might fail to power off or power on.
> +		 */
> +		atpx->functions.power_cntl = !radeon_atpx_priv.bridge_pm_usable;
>  		atpx->is_hybrid = true;
>  	}
>  
> @@ -474,6 +479,7 @@ static int radeon_atpx_power_state(enum vga_switcheroo_client_id id,
>   */
>  static bool radeon_atpx_pci_probe_handle(struct pci_dev *pdev)
>  {
> +	struct pci_dev *parent_pdev = pci_upstream_bridge(pdev);
>  	acpi_handle dhandle, atpx_handle;
>  	acpi_status status;
>  
> @@ -487,6 +493,7 @@ static bool radeon_atpx_pci_probe_handle(struct pci_dev *pdev)
>  
>  	radeon_atpx_priv.dhandle = dhandle;
>  	radeon_atpx_priv.atpx.handle = atpx_handle;
> +	radeon_atpx_priv.bridge_pm_usable = parent_pdev && parent_pdev->bridge_d3;
>  	return true;
>  }
>  
> -- 
> 2.5.5