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

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 <fdporg@vega.pgw.jp>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: x86@kernel.org
Cc: stable@vger.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 <fdporg@vega.pgw.jp>
Tested-by: Taketo Kabe <fdporg@vega.pgw.jp>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=96473
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
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 <chris@chris-wilson.co.uk>

diff --git a/arch/x86/kernel/early-quirks.c b/arch/x86/kernel/early-quirks.c
index de7501e..8b8852b 100644 (file)
--- a/arch/x86/kernel/early-quirks.c
+++ b/arch/x86/kernel/early-quirks.c
@@ -317,16 +317,11 @@ static phys_addr_t __init i85x_stolen_base(int num, int slot, int func,
 static phys_addr_t __init i865_stolen_base(int num, int slot, int func,
                                           size_t stolen_size)
 {
-       u16 toud;
+       u16 toud = 0;
 
-       /*
-        * FIXME is the graphics stolen memory region
-        * always at TOUD? Ie. is it always the last
-        * one to be allocated by the BIOS?
-        */
        toud = read_pci_config_16(0, 0, 0, I865_TOUD);
 
-       return (phys_addr_t)toud << 16;
+       return (phys_addr_t)(toud << 16) + i845_tseg_size();
 }
 
 static phys_addr_t __init gen3_stolen_base(int num, int slot, int func,

diff --git a/drivers/gpu/drm/i915/i915_gem_stolen.c b/drivers/gpu/drm/i915/i915_gem_stolen.c
index 1327961..f763358 100644 (file)
--- a/drivers/gpu/drm/i915/i915_gem_stolen.c
+++ b/drivers/gpu/drm/i915/i915_gem_stolen.c
@@ -115,17 +115,28 @@ static unsigned long i915_stolen_to_physical(struct drm_device *dev)
 
                base = bsm & INTEL_BSM_MASK;
        } 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;