Messages in this thread Patch in this message | | | Subject | [PATCH] Reduce extraneous PCI posting reads during Intel AGP initialization | From | Keith Packard <> | Date | Mon, 13 Oct 2008 23:40:11 -0700 |
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From b4ca8f9596e3d5d2a4c090eaf5e4f373c131a476 Mon Sep 17 00:00:00 2001 From: Keith Packard <keithp@keithp.com> Date: Mon, 13 Oct 2008 23:33:21 -0700 Subject: [PATCH] Reduce extraneous PCI posting reads during Intel AGP initialization
Instead of doing a posting read after each GTT entry update, do a single one at the end of the writes. This should reduce boot time a tiny amount by avoiding a lot of extra uncached reads.
Signed-off-by: Keith Packard <keithp@keithp.com> --- drivers/char/agp/intel-agp.c | 6 +++--- 1 files changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/char/agp/intel-agp.c b/drivers/char/agp/intel-agp.c index 016fdf0..a6a0c34 100644 --- a/drivers/char/agp/intel-agp.c +++ b/drivers/char/agp/intel-agp.c @@ -214,8 +214,8 @@ static int intel_i810_configure(void) if (agp_bridge->driver->needs_scratch_page) { for (i = 0; i < current_size->num_entries; i++) { writel(agp_bridge->scratch_page, intel_private.registers+I810_PTE_BASE+(i*4)); - readl(intel_private.registers+I810_PTE_BASE+(i*4)); /* PCI posting. */ } + readl(intel_private.registers+I810_PTE_BASE+((i-1)*4)); /* PCI posting. */ } global_cache_flush(); return 0; @@ -773,8 +773,8 @@ static int intel_i830_configure(void) if (agp_bridge->driver->needs_scratch_page) { for (i = intel_private.gtt_entries; i < current_size->num_entries; i++) { writel(agp_bridge->scratch_page, intel_private.registers+I810_PTE_BASE+(i*4)); - readl(intel_private.registers+I810_PTE_BASE+(i*4)); /* PCI Posting. */ } + readl(intel_private.registers+I810_PTE_BASE+((i-1)*4)); /* PCI Posting. */ } global_cache_flush(); @@ -989,8 +989,8 @@ static int intel_i915_configure(void) if (agp_bridge->driver->needs_scratch_page) { for (i = intel_private.gtt_entries; i < current_size->num_entries; i++) { writel(agp_bridge->scratch_page, intel_private.gtt+i); - readl(intel_private.gtt+i); /* PCI Posting. */ } + readl(intel_private.gtt+i-1); /* PCI Posting. */ } global_cache_flush(); -- 1.5.6.5
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