linux-kernel - Re: [PATCH 4.8 14/37] drm/amdgpu: fix power state when port pm is unavailable

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Message-ID: <20161130105100.GA20293@al>
Date:   Wed, 30 Nov 2016 11:51:00 +0100
From:   Peter Wu <peter@...ensteyn.nl>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     linux-kernel@...r.kernel.org, stable@...r.kernel.org,
        Alex Deucher <alexander.deucher@....com>,
        Christian König <christian.koenig@....com>
Subject: Re: [PATCH 4.8 14/37] drm/amdgpu: fix power state when port pm is
 unavailable


Hi Greg,

On Wed, Nov 30, 2016 at 10:29:51AM +0100, Greg Kroah-Hartman wrote:
> 4.8-stable review patch.  If anyone has any objections, please let me know.

Please delay this patch (amd tje mext radeon patch, 15/37), it contains
a regression for which these patches (from drm-fixes) are needed:

    drm/radeon: fix check for port PM availability
    drm/amdgpu: fix check for port PM availability

Patches should appear in v4.9-rc8 via
https://cgit.freedesktop.org/~airlied/linux/log/?h=drm-fixes

Kind regards,
Peter

> ------------------
> 
> From: Peter Wu <peter@...ensteyn.nl>
> 
> commit 1db4496f167bcc7c6541d449355ade2e7d339d52 upstream.
> 
> 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.
> 
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=98505
> Reported-and-tested-by: Nayan Deshmukh <nayan26deshmukh@...il.com>
> Signed-off-by: Peter Wu <peter@...ensteyn.nl>
> Signed-off-by: Alex Deucher <alexander.deucher@....com>
> Acked-by: Christian König <christian.koenig@....com>
> Reviewed-by: Alex Deucher <alexander.deucher@....com>
> Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
> 
> ---
>  drivers/gpu/drm/amd/amdgpu/amdgpu_atpx_handler.c |    9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)
> 
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_atpx_handler.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_atpx_handler.c
> @@ -33,6 +33,7 @@ struct amdgpu_atpx {
>  
>  static struct amdgpu_atpx_priv {
>  	bool atpx_detected;
> +	bool bridge_pm_usable;
>  	/* handle for device - and atpx */
>  	acpi_handle dhandle;
>  	acpi_handle other_handle;
> @@ -200,7 +201,11 @@ static int amdgpu_atpx_validate(struct a
>  	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 = !amdgpu_atpx_priv.bridge_pm_usable;
>  		atpx->is_hybrid = true;
>  	}
>  
> @@ -471,6 +476,7 @@ static int amdgpu_atpx_power_state(enum
>   */
>  static bool amdgpu_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;
>  
> @@ -485,6 +491,7 @@ static bool amdgpu_atpx_pci_probe_handle
>  	}
>  	amdgpu_atpx_priv.dhandle = dhandle;
>  	amdgpu_atpx_priv.atpx.handle = atpx_handle;
> +	amdgpu_atpx_priv.bridge_pm_usable = parent_pdev && parent_pdev->bridge_d3;
>  	return true;
>  }
>  
> 
>