This is a note to let you know that I've just added the patch titled
drm/ast: Remove existing framebuffers before loading driver
to the 4.9-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-ast-remove-existing-framebuffers-before-loading-driver.patch
and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 5478ad10e7850ce3d8b7056db05ddfa3c9ddad9a Mon Sep 17 00:00:00 2001
From: Thomas Zimmermann <tzimmermann@xxxxxxx>
Date: Thu, 15 Nov 2018 11:42:16 +0100
Subject: drm/ast: Remove existing framebuffers before loading driver
From: Thomas Zimmermann <tzimmermann@xxxxxxx>
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@xxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Tested-by: Y.C. Chen <yc_chen@xxxxxxxxxxxxxx>
Reviewed-by: Jean Delvare <jdelvare@xxxxxxx>
Tested-by: Jean Delvare <jdelvare@xxxxxxx>
Signed-off-by: Dave Airlie <airlied@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/gpu/drm/ast/ast_drv.c | 21 +++++++++++++++++++++
1 file changed, 21 insertions(+)
--- a/drivers/gpu/drm/ast/ast_drv.c
+++ b/drivers/gpu/drm/ast/ast_drv.c
@@ -60,8 +60,29 @@ static const struct pci_device_id pciidl
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);
}
Patches currently in stable-queue which might be from tzimmermann@xxxxxxx are
queue-4.9/drm-ast-remove-existing-framebuffers-before-loading-driver.patch
