From: Chris Wilson <chris@chris-wilson.co.uk>
Date: Wed, 7 Feb 2018 22:28:24 +0000
Subject: drm/i915: Wait for gen3 reset status to be asserted
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Git-commit: a1ab7dcf634f9e5f8e8d25fec4cc4d46602c146c
Patch-mainline: v4.17-rc1
References: FATE#326289 FATE#326079 FATE#326049 FATE#322398 FATE#326166
After we assert the reset request (and wait for 20us), when the device
has been fully reset it asserts the reset-status bit. Before we stop
requesting the reset and allow the device to return to normal, we should
wait for the reset to be completed. (Similar to how we wait for the
device to return to normal after deasserting the reset request.)
v2: Rename i915_reset_completed() probe to not cause as much confusion.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180207222824.29864-1-chris@chris-wilson.co.uk
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Acked-by: Petr Tesarik <ptesarik@suse.com>
---
drivers/gpu/drm/i915/intel_uncore.c | 15 +++++++++++----
1 file changed, 11 insertions(+), 4 deletions(-)
--- a/drivers/gpu/drm/i915/intel_uncore.c
+++ b/drivers/gpu/drm/i915/intel_uncore.c
@@ -1550,24 +1550,31 @@ static void i915_stop_engines(struct drm
gen3_stop_engine(engine);
}
-static bool i915_reset_complete(struct pci_dev *pdev)
+static bool i915_in_reset(struct pci_dev *pdev)
{
u8 gdrst;
pci_read_config_byte(pdev, I915_GDRST, &gdrst);
- return (gdrst & GRDOM_RESET_STATUS) == 0;
+ return gdrst & GRDOM_RESET_STATUS;
}
static int i915_do_reset(struct drm_i915_private *dev_priv, unsigned engine_mask)
{
struct pci_dev *pdev = dev_priv->drm.pdev;
+ int err;
- /* assert reset for at least 20 usec */
+ /* Assert reset for at least 20 usec, and wait for acknowledgement. */
pci_write_config_byte(pdev, I915_GDRST, GRDOM_RESET_ENABLE);
usleep_range(50, 200);
+ err = wait_for(i915_in_reset(pdev), 500);
+
+ /* Clear the reset request. */
pci_write_config_byte(pdev, I915_GDRST, 0);
+ usleep_range(50, 200);
+ if (!err)
+ err = wait_for(!i915_in_reset(pdev), 500);
- return wait_for(i915_reset_complete(pdev), 500);
+ return err;
}
static bool g4x_reset_complete(struct pci_dev *pdev)