Commit 0bf67de5 authored Nov 15, 2018 by Thomas Zimmermann Committed by Greg Kroah-Hartman Dec 01, 2018

drm/ast: Remove existing framebuffers before loading driver

commit 5478ad10e7850ce3d8b7056db05ddfa3c9ddad9a upstream.

If vesafb attaches to the AST device, it configures the framebuffer memory
for uncached access by default. When ast.ko later tries to attach itself to
the device, it wants to use write-combining on the framebuffer memory, but
vesefb's existing configuration for uncached access takes precedence. This
results in reduced performance.

Removing the framebuffer's configuration before loding the AST driver fixes
the problem. Other DRM drivers already contain equivalent code.

Link: https://bugzilla.opensuse.org/show_bug.cgi?id=1112963


Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Cc: <stable@vger.kernel.org>
Tested-by: Y.C. Chen <yc_chen@aspeedtech.com>
Reviewed-by: Jean Delvare <jdelvare@suse.de>
Tested-by: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 7fdaacc0

drivers/gpu/drm/ast/ast_drv.c

+21 −0

Original line number	Diff line number	Diff line
		@@ -60,8 +60,29 @@ static const struct pci_device_id pciidlist[] = {

		MODULE_DEVICE_TABLE(pci, pciidlist);

		static void ast_kick_out_firmware_fb(struct pci_dev *pdev)
		{
		struct apertures_struct *ap;
		bool primary = false;

		ap = alloc_apertures(1);
		if (!ap)
		return;

		ap->ranges[0].base = pci_resource_start(pdev, 0);
		ap->ranges[0].size = pci_resource_len(pdev, 0);

		#ifdef CONFIG_X86
		primary = pdev->resource[PCI_ROM_RESOURCE].flags & IORESOURCE_ROM_SHADOW;
		#endif
		drm_fb_helper_remove_conflicting_framebuffers(ap, "astdrmfb", primary);
		kfree(ap);
		}

		static int ast_pci_probe(struct pci_dev pdev, const struct pci_device_id ent)
		{
		ast_kick_out_firmware_fb(pdev);

		return drm_get_pci_dev(pdev, ent, &driver);
		}