[PATCH] drm/i915: fix crash in error state readout on non-execlist platforms v2

Jesse Barnes
2015-09-15T17:03:12Z

Looks like this was introduced in:
commit d1675198ed1f21aec6e036336e4340c40b726497
Author: Alex Dai <yu.dai@intel.com>
Date: Wed Aug 12 15:43:43 2015 +0100

drm/i915: Integrate GuC-based command submission

This patch assumed LRC contexts and HWS layout, which is incorrect on
platforms without execlists. This can lead to a crash in GPU error
state readout on those platforms.

I don't see a bug filed for this, but there may be one that I haven't
found.

v2: fixup offset handling for error capture fix (Dave)

Cc: Alex Dai <yu.dai@intel.com>
Reviewed-by: Dave Gordon <david.s.gordon@intel.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
---
drivers/gpu/drm/i915/i915_gpu_error.c | 18 ++++++++++++------
1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gpu_error.c b/drivers/gpu/drm/i915/i915_gpu_error.c
index 3379f9c..f95de05 100644
--- a/drivers/gpu/drm/i915/i915_gpu_error.c
+++ b/drivers/gpu/drm/i915/i915_gpu_error.c
@@ -457,17 +457,23 @@ int i915_error_state_to_str(struct drm_i915_error_state_buf *m,
}

if ((obj = error->ring[i].hws_page)) {
+ u64 hws_offset = obj->gtt_offset;
+ u32 *hws_page = &obj->pages[0][0];
+
+ if (i915.enable_execlists) {
+ hws_offset += LRC_PPHWSP_PN * PAGE_SIZE;
+ hws_page = &obj->pages[LRC_PPHWSP_PN][0];
+ }
err_printf(m, "%s --- HW Status = 0x%08llx\n",
- dev_priv->ring[i].name,
- obj->gtt_offset + LRC_PPHWSP_PN * PAGE_SIZE);
+ dev_priv->ring[i].name, hws_offset);
offset = 0;
for (elt = 0; elt < PAGE_SIZE/16; elt += 4) {
err_printf(m, "[%04x] %08x %08x %08x %08x\n",
offset,
- obj->pages[LRC_PPHWSP_PN][elt],
- obj->pages[LRC_PPHWSP_PN][elt+1],
- obj->pages[LRC_PPHWSP_PN][elt+2],
- obj->pages[LRC_PPHWSP_PN][elt+3]);
+ hws_page[elt],
+ hws_page[elt+1],
+ hws_page[elt+2],
+ hws_page[elt+3]);
offset += 16;
}
}
--
1.9.1