Patch "drm/i915: Account for TSEG size when determining 865G stolen base" has been added to the 4.4-stable tree

This is a note to let you know that I've just added the patch titled

    drm/i915: Account for TSEG size when determining 865G stolen base

to the 4.4-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-i915-account-for-tseg-size-when-determining-865g-stolen-base.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let [off-list ref] know about it.

From d721b02fd00bf133580f431b82ef37f3b746dfb2 Mon Sep 17 00:00:00 2001

From: =?UTF-8?q?Ville=20Syrj=C3=A4l=C3=A4?= <redacted>
Date: Mon, 8 Aug 2016 13:58:39 +0300
Subject: drm/i915: Account for TSEG size when determining 865G stolen base
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From: Ville Syrjälä <redacted>

commit d721b02fd00bf133580f431b82ef37f3b746dfb2 upstream.

Looks like the TSEG lives just above TOUD, stolen comes after TSEG.

The spec seems somewhat self-contradictory in places, in the ESMRAMC
register desctription it says:
 TSEG Size:
  10=(TOUD + 512 KB) to TOUD
  11 =(TOUD + 1 MB) to TOUD

so that agrees with TSEG being at TOUD. But the example given
elsehwere in the spec says:

 TOUD equals 62.5 MB = 03E7FFFFh
 TSEG selected as 512 KB in size,
 Graphics local memory selected as 1 MB in size
 General System RAM available in system = 62.5 MB
 General system RAM range00000000h to 03E7FFFFh
 TSEG address range03F80000h to 03FFFFFFh
 TSEG pre-allocated from03F80000h to 03FFFFFFh
 Graphics local memory pre-allocated from03E80000h to 03F7FFFFh

so here we have TSEG above stolen.

Real world evidence agrees with the TOUD->TSEG->stolen order however, so
let's fix up the code to account for the TSEG size.

Cc: Taketo Kabe <redacted>
Cc: Chris Wilson <redacted>
Cc: Daniel Vetter <redacted>
Cc: Thomas Gleixner <redacted>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: x86@kernel.org
Fixes: 0ad98c74e093 ("drm/i915: Determine the stolen memory base address on gen2")
Fixes: a4dff76924fe ("x86/gpu: Add Intel graphics stolen memory quirk for gen2 platforms")
Reported-by: Taketo Kabe <redacted>
Tested-by: Taketo Kabe <redacted>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=96473
Signed-off-by: Ville Syrjälä <redacted>
Link: http://patchwork.freedesktop.org/patch/msgid/1470653919-27251-1-git-send-email-ville.syrjala@linux.intel.com
Link: http://download.intel.com/design/chipsets/datashts/25251405.pdf
Reviewed-by: Chris Wilson <redacted>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 arch/x86/kernel/early-quirks.c         |   11 +++++------
 drivers/gpu/drm/i915/i915_gem_stolen.c |   23 +++++++++++++++++------
 2 files changed, 22 insertions(+), 12 deletions(-)

--- a/arch/x86/kernel/early-quirks.c
+++ b/arch/x86/kernel/early-quirks.c

@@ -331,12 +331,11 @@ static u32 __init i85x_stolen_base(int n
 
 static u32 __init i865_stolen_base(int num, int slot, int func, size_t stolen_size)
 {
-	/*
-	 * FIXME is the graphics stolen memory region
-	 * always at TOUD? Ie. is it always the last
-	 * one to be allocated by the BIOS?
-	 */
-	return read_pci_config_16(0, 0, 0, I865_TOUD) << 16;
+	u16 toud = 0;
+
+	toud = read_pci_config_16(0, 0, 0, I865_TOUD);
+
+	return (phys_addr_t)(toud << 16) + i845_tseg_size();
 }
 
 static size_t __init i830_stolen_size(int num, int slot, int func)
--- a/drivers/gpu/drm/i915/i915_gem_stolen.c
+++ b/drivers/gpu/drm/i915/i915_gem_stolen.c

@@ -108,17 +108,28 @@ static unsigned long i915_stolen_to_phys
 		pci_read_config_dword(dev->pdev, 0x5c, &base);
 		base &= ~((1<<20) - 1);
 	} else if (IS_I865G(dev)) {
+		u32 tseg_size = 0;
 		u16 toud = 0;
+		u8 tmp;
+
+		pci_bus_read_config_byte(dev->pdev->bus, PCI_DEVFN(0, 0),
+					 I845_ESMRAMC, &tmp);
+
+		if (tmp & TSEG_ENABLE) {
+			switch (tmp & I845_TSEG_SIZE_MASK) {
+			case I845_TSEG_SIZE_512K:
+				tseg_size = KB(512);
+				break;
+			case I845_TSEG_SIZE_1M:
+				tseg_size = MB(1);
+				break;
+			}
+		}
 
-		/*
-		 * FIXME is the graphics stolen memory region
-		 * always at TOUD? Ie. is it always the last
-		 * one to be allocated by the BIOS?
-		 */
 		pci_bus_read_config_word(dev->pdev->bus, PCI_DEVFN(0, 0),
 					 I865_TOUD, &toud);
 
-		base = toud << 16;
+		base = (toud << 16) + tseg_size;
 	} else if (IS_I85X(dev)) {
 		u32 tseg_size = 0;
 		u32 tom;

Patches currently in stable-queue which might be from ville.syrjala@linux.intel.com are

queue-4.4/drm-i915-account-for-tseg-size-when-determining-865g-stolen-base.patch