Patch "drm/amdgpu: fix check for port PM availability" has been added to the 4.8-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    drm/amdgpu: fix check for port PM availability

to the 4.8-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     drm-amdgpu-fix-check-for-port-pm-availability.patch
and it can be found in the queue-4.8 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 7ac33e47d5769632010e537964c7e45498f8dc26 Mon Sep 17 00:00:00 2001
From: Peter Wu <peter@lekensteyn.nl>
Date: Sat, 26 Nov 2016 15:05:01 +0100
Subject: drm/amdgpu: fix check for port PM availability

From: Peter Wu <peter@lekensteyn.nl>

commit 7ac33e47d5769632010e537964c7e45498f8dc26 upstream.

The ATPX method does not always exist on the dGPU, it may be located at
the iGPU. The parent device of the iGPU is the root port for which
bridge_d3 is false. This accidentally enables the legacy PM method which
conflicts with port PM and prevented the dGPU from powering on.

Fixes: 1db4496f167b ("drm/amdgpu: fix power state when port pm is unavailable")

Reported-and-tested-by: Mike Lothian <mike@fireburn.co.uk>
Signed-off-by: Peter Wu <peter@lekensteyn.nl>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/gpu/drm/amd/amdgpu/amdgpu_atpx_handler.c |   11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_atpx_handler.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_atpx_handler.c
@@ -476,7 +476,6 @@ 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;
 
@@ -491,7 +490,6 @@ 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;
 }
 
@@ -553,17 +551,25 @@ static bool amdgpu_atpx_detect(void)
 	struct pci_dev *pdev = NULL;
 	bool has_atpx = false;
 	int vga_count = 0;
+	bool d3_supported = false;
+	struct pci_dev *parent_pdev;
 
 	while ((pdev = pci_get_class(PCI_CLASS_DISPLAY_VGA << 8, pdev)) != NULL) {
 		vga_count++;
 
 		has_atpx |= (amdgpu_atpx_pci_probe_handle(pdev) == true);
+
+		parent_pdev = pci_upstream_bridge(pdev);
+		d3_supported |= parent_pdev && parent_pdev->bridge_d3;
 	}
 
 	while ((pdev = pci_get_class(PCI_CLASS_DISPLAY_OTHER << 8, pdev)) != NULL) {
 		vga_count++;
 
 		has_atpx |= (amdgpu_atpx_pci_probe_handle(pdev) == true);
+
+		parent_pdev = pci_upstream_bridge(pdev);
+		d3_supported |= parent_pdev && parent_pdev->bridge_d3;
 	}
 
 	if (has_atpx && vga_count == 2) {
@@ -571,6 +577,7 @@ static bool amdgpu_atpx_detect(void)
 		printk(KERN_INFO "vga_switcheroo: detected switching method %s handle\n",
 		       acpi_method_name);
 		amdgpu_atpx_priv.atpx_detected = true;
+		amdgpu_atpx_priv.bridge_pm_usable = d3_supported;
 		amdgpu_atpx_init();
 		return true;
 	}


Patches currently in stable-queue which might be from peter@lekensteyn.nl are

queue-4.8/drm-radeon-fix-power-state-when-port-pm-is-unavailable-v2.patch
queue-4.8/drm-amdgpu-fix-power-state-when-port-pm-is-unavailable.patch
queue-4.8/drm-radeon-fix-check-for-port-pm-availability.patch
queue-4.8/drm-amdgpu-fix-check-for-port-pm-availability.patch