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authorAlex Williamson <alex.williamson@redhat.com>2013-08-28 19:39:08 +0400
committerDaniel Vetter <daniel.vetter@ffwll.ch>2013-09-03 21:17:59 +0400
commit81b5c7bc8de3e6f63419139c2fc91bf81dea8a7d (patch)
treef7b04c2dad467cc072c774c7b7dbbd6d179f4eee /include/linux/vgaarb.h
parent5c0f6ee766d7c689e71a7df5e5fa87941affd75a (diff)
downloadlinux-81b5c7bc8de3e6f63419139c2fc91bf81dea8a7d.tar.xz
i915: Update VGA arbiter support for newer devices
This is intended to add VGA arbiter support for Intel HD graphics on Core processors. The old GMCH registers no longer exist, so even though it appears that i915 participates in VGA arbitration, it doesn't work. On Intel HD graphics we already attempt to disable VGA regions of the device. This makes registering as a VGA client unnecessary since we don't intend to operate differently depending on how many VGA devices are present. We can disable VGA memory regions by clearing the memory enable bit in the VGA MSR. That only leaves VGA IO, which we update the VGA arbiter to know that we don't participate in VGA memory arbitration. We also add a hook on unload to re-enable memory and reinstate VGA memory arbitration. v3: Use explicit LEGACY_IO | LEGACY_MEM when restoring rather than LEGACY_MASK, per Ville's comments. v2: I915_READ/WRITE accessors don't work in i915_disable_vga, use inb/outb directly. Also, on the driver unbind VGA enable path, acquire legacy IO to re-enable VGA memory. Correct comment. Signed-off-by: Alex Williamson <alex.williamson@redhat.com> Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com> [danvet: Add patch changelog. Also squash in a fixup to have a dummy static inline for vga_set_legacy_decoding for CONFIG_VGA_ARB=n as reported by the 0-day kernel build bot.] Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> fixup 2
Diffstat (limited to 'include/linux/vgaarb.h')
-rw-r--r--include/linux/vgaarb.h7
1 files changed, 7 insertions, 0 deletions
diff --git a/include/linux/vgaarb.h b/include/linux/vgaarb.h
index 2c02f3a8d2ba..80cf8173a65b 100644
--- a/include/linux/vgaarb.h
+++ b/include/linux/vgaarb.h
@@ -65,8 +65,15 @@ struct pci_dev;
* out of the arbitration process (and can be safe to take
* interrupts at any time.
*/
+#if defined(CONFIG_VGA_ARB)
extern void vga_set_legacy_decoding(struct pci_dev *pdev,
unsigned int decodes);
+#else
+static inline void vga_set_legacy_decoding(struct pci_dev *pdev,
+ unsigned int decodes)
+{
+}
+#endif
/**
* vga_get - acquire & locks VGA resources