[PATCH] drm/i915: add more debug info for when atomic updates fail v2

Jesse Barnes
2015-09-15T17:03:46Z

I used these additional fields to track down the issue I saw on HSW.

v2: move debug fields into a substruct (Ville)

References: https://bugs.freedesktop.org/show_bug.cgi?id=91579
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
---
drivers/gpu/drm/i915/intel_drv.h | 8 ++++++--
drivers/gpu/drm/i915/intel_sprite.c | 30 +++++++++++++++++++++---------
2 files changed, 27 insertions(+), 11 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 02a755a..1df6ebf 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -565,8 +565,12 @@ struct intel_crtc {

int scanline_offset;

- unsigned start_vbl_count;
- ktime_t start_vbl_time;
+ struct {
+ unsigned start_vbl_count;
+ ktime_t start_vbl_time;
+ int min_vbl, max_vbl;
+ int scanline_start;
+ } debug;

struct intel_crtc_atomic_commit atomic;

diff --git a/drivers/gpu/drm/i915/intel_sprite.c b/drivers/gpu/drm/i915/intel_sprite.c
index 4d27243..4c627c4 100644
--- a/drivers/gpu/drm/i915/intel_sprite.c
+++ b/drivers/gpu/drm/i915/intel_sprite.c
@@ -94,8 +94,11 @@ void intel_pipe_update_start(struct intel_crtc *crtc)
min = vblank_start - usecs_to_scanlines(mode, 100);
max = vblank_start - 1;

+ crtc->debug.min_vbl = min;
+ crtc->debug.max_vbl = max;
+
local_irq_disable();
- crtc->start_vbl_count = 0;
+ crtc->debug.start_vbl_count = 0;

if (min <= 0 || max <= 0)
return;
@@ -114,8 +117,10 @@ void intel_pipe_update_start(struct intel_crtc *crtc)
prepare_to_wait(wq, &wait, TASK_UNINTERRUPTIBLE);

scanline = intel_get_crtc_scanline(crtc);
- if (scanline < min || scanline > max)
+ if (scanline < min || scanline > max) {
+ crtc->debug.scanline_start = scanline;
break;
+ }

if (timeout <= 0) {
DRM_ERROR("Potential atomic update failure on pipe %c\n",
@@ -134,11 +139,12 @@ void intel_pipe_update_start(struct intel_crtc *crtc)

drm_crtc_vblank_put(&crtc->base);

- crtc->start_vbl_time = ktime_get();
- crtc->start_vbl_count = dev->driver->get_vblank_counter(dev, pipe);
+ crtc->debug.start_vbl_time = ktime_get();
+ crtc->debug.start_vbl_count =
+ dev->driver->get_vblank_counter(dev, pipe);

trace_i915_pipe_update_vblank_evaded(crtc, min, max,
- crtc->start_vbl_count);
+ crtc->debug.start_vbl_count);
}

/**
@@ -161,10 +167,16 @@ void intel_pipe_update_end(struct intel_crtc *crtc)

local_irq_enable();

- if (crtc->start_vbl_count && crtc->start_vbl_count != end_vbl_count)
- DRM_ERROR("Atomic update failure on pipe %c (start=%u end=%u) time %lld us\n",
- pipe_name(pipe), crtc->start_vbl_count, end_vbl_count,
- ktime_us_delta(end_vbl_time, crtc->start_vbl_time));
+ if (crtc->debug.start_vbl_count &&
+ crtc->debug.start_vbl_count != end_vbl_count) {
+ DRM_ERROR("Atomic update failure on pipe %c (start=%u end=%u) time %lld us, min %d, max %d, scanline start %d, end %d\n",
+ pipe_name(pipe), crtc->debug.start_vbl_count,
+ end_vbl_count,
+ ktime_us_delta(end_vbl_time, crtc->debug.start_vbl_time),
+ crtc->debug.min_vbl, crtc->debug.max_vbl,
+ crtc->debug.scanline_start,
+ intel_get_crtc_scanline(crtc));
+ }
}

static void
--
1.9.1