From e9a4099a59cc598a44006059dd775c25e422b772 Mon Sep 17 00:00:00 2001
From: Alex Deucher <alexdeucher@gmail.com>
Date: Tue, 15 Apr 2014 12:44:34 -0400
Subject: [PATCH] drm/radeon: fix ATPX detection on non-VGA GPUs
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Some newer PX laptops have the pci device class
set to DISPLAY_OTHER rather than DISPLAY_VGA.  This
properly detects ATPX on those laptops.

Based on a patch from: Pali Rohár <pali.rohar@gmail.com>

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
Cc: airlied@gmail.com
---
 drivers/gpu/drm/radeon/radeon_atpx_handler.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/gpu/drm/radeon/radeon_atpx_handler.c b/drivers/gpu/drm/radeon/radeon_atpx_handler.c
index dedea72f48c45..a9fb0d016d387 100644
--- a/drivers/gpu/drm/radeon/radeon_atpx_handler.c
+++ b/drivers/gpu/drm/radeon/radeon_atpx_handler.c
@@ -528,6 +528,13 @@ static bool radeon_atpx_detect(void)
 		has_atpx |= (radeon_atpx_pci_probe_handle(pdev) == true);
 	}
 
+	/* some newer PX laptops mark the dGPU as a non-VGA display device */
+	while ((pdev = pci_get_class(PCI_CLASS_DISPLAY_OTHER << 8, pdev)) != NULL) {
+		vga_count++;
+
+		has_atpx |= (radeon_atpx_pci_probe_handle(pdev) == true);
+	}
+
 	if (has_atpx && vga_count == 2) {
 		acpi_get_name(radeon_atpx_priv.atpx.handle, ACPI_FULL_PATHNAME, &buffer);
 		printk(KERN_INFO "VGA switcheroo: detected switching method %s handle\n",
-- 
2.39.5