[Intel-gfx] [PATCH 3/5] drm/i915: clear FPGA_DBG_RM_NOCLAIM when capturing error state

[Paulo Zanoni]

From: Paulo Zanoni <paulo.r.zanoni at intel.com>

In the error state function we read the registers without checking if
the power well is on, so after doing this we have to clear the
FPGA_DBG_RM_NOCLAIM bit to prevent the next I915_WRITE from detecting
it and printing an error message.

The first version of this patch was checking for the power well state
and then avoiding reading registers that were off, but the reviewers
requested to just read the registers any way and then later clear the
FPGA_DBG_RM_NOCLAIM bit.

Signed-off-by: Paulo Zanoni <paulo.r.zanoni at intel.com>
Reviewed-by: Damien Lespiau <damien.lespiau at intel.com>
---
 drivers/gpu/drm/i915/intel_display.c |    7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 190b787..fcb1367 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -9826,6 +9826,13 @@ intel_display_capture_error_state(struct drm_device *dev)
 		error->pipe[i].vsync = I915_READ(VSYNC(cpu_transcoder));
 	}
 
+	/* In the code above we read the registers without checking if the power
+	 * well was on, so here we have to clear the FPGA_DBG_RM_NOCLAIM bit to
+	 * prevent the next I915_WRITE from detecting it and printing an error
+	 * message. */
+	if (HAS_POWER_WELL(dev))
+		I915_WRITE_NOTRACE(FPGA_DBG, FPGA_DBG_RM_NOCLAIM);
+
 	return error;
 }
 
-- 
1.7.10.4