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75 lines
2.2 KiB
75 lines
2.2 KiB
From: Brandon Philips <bphilips@suse.de>
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Subject: Avoid oops on G33 in 1MB stolen Mem case
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References: bnc#391261
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Patch-Mainline: soon (see bug for ref)
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This is similar to f443675affe3f16dd428e46f0f7fd3f4d703eeab which was
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reverted because it broke with older XOrg driver. This patch only fixes
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the 1MB stolen case since it causes an oops due to a calculation
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problem.
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This will not work with older X drivers without the accompanying patch
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but I think avoiding an oops and making it possible to work with an
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up-to-date xorg driver is reasonable.
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Explanation of the oops:
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> static void intel_i830_init_gtt_entries(void)
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...
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> } else if (IS_G33) {
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> /* G33's GTT size defined in gmch_ctrl */
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> switch (gmch_ctrl & G33_PGETBL_SIZE_MASK) {
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> case G33_PGETBL_SIZE_1M:
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> size = 1024;
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> break;
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...
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> size += 4;
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size = 1028
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Then since we have the BIOS setting 1MB for the device in the GMCH
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control we get to here:
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> } else {
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> switch (gmch_ctrl & I855_GMCH_GMS_MASK) {
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> case I855_GMCH_GMS_STOLEN_1M:
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> gtt_entries = MB(1) - KB(size);
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> break;
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MB(1) = 1 * 1024 * 1024
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KB(1028) = 1028 * 1024
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MB(1) - KB(1028) = -4096
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> gtt_entries /= KB(4);
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> intel_private.gtt_entries = gtt_entries;
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We end up with -1 in gtt_entries.
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This leads to intel_i915_configure reading/writing to areas outside of
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mapped memory and the oops.
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Signed-off-by: Brandon Philips <bphilips@suse.de>
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Acked-by: Thomas Renninger <trenn@suse.de>
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---
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drivers/char/agp/intel-agp.c | 7 +++++++
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1 file changed, 7 insertions(+)
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--- a/drivers/char/agp/intel-agp.c
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+++ b/drivers/char/agp/intel-agp.c
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@@ -801,6 +801,13 @@ static void intel_i830_init_gtt_entries(
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} else {
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switch (gmch_ctrl & I855_GMCH_GMS_MASK) {
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case I855_GMCH_GMS_STOLEN_1M:
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+ if (IS_G33) {
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+ size = 0;
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+ printk(KERN_WARNING PFX
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+ "Warning: G33 chipset with 1MB"
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+ " allocated. Older X.org Intel drivers"
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+ " will not work.\n");
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+ }
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gtt_entries = MB(1) - KB(size);
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break;
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case I855_GMCH_GMS_STOLEN_4M:
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