drm/radeon: fix ATPX detection on non-VGA GPUs

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

diff --git a/drivers/gpu/drm/radeon/radeon_atpx_handler.c b/drivers/gpu/drm/radeon/radeon_atpx_handler.c
index dedea72..a9fb0d0 100644 (file)
--- 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",