[Intel-gfx] [PATCH 1/2] drm/i915: FPGA_DBG is display-specific

* [Intel-gfx] [PATCH 1/2] drm/i915: FPGA_DBG is display-specific
@ 2021-02-12 21:19 Matt Roper
  2021-02-12 21:19 ` [Intel-gfx] [PATCH 2/2] drm/i915: Try to detect sudden loss of MMIO access Matt Roper
                   ` (7 more replies)
  0 siblings, 8 replies; 11+ messages in thread
From: Matt Roper @ 2021-02-12 21:19 UTC (permalink / raw
  To: intel-gfx; +Cc: Lucas De Marchi

Although the bspec's description doesn't make it very clear, the
hardware architects have confirmed that the FPGA_DBG register that we
use to check for unclaimed MMIO accesses is display-specific and will
only properly flag unclaimed MMIO transactions for registers in the
display range.  If a platform doesn't have display, FPGA_DBG itself will
not be available and should not be checked.  Let's move the feature flag
into intel_device_info.display to more accurately reflect this.

Given that we now know FPGA_DBG is display-specific, it could be argued
that we should only check it on out intel_de_*() functions.  However
let's not make that change right now; keeping the checks in all of the
existing locations still helps us catch cases where regular
intel_uncore_*() functions use bad MMIO offset math / base addresses and
accidentally wind up landing within an unused area within the display
MMIO range.  It will also help catch cases where userspace-initiated
MMIO (e.g., IGT's intel_reg tool) attempt to read bad offsets within the
display range.

Cc: Lucas De Marchi <lucas.demarchi@intel.com>
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
---
 drivers/gpu/drm/i915/i915_pci.c          | 4 ++--
 drivers/gpu/drm/i915/intel_device_info.h | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_pci.c b/drivers/gpu/drm/i915/i915_pci.c
index eff7155db2fd..a9f24f2bda33 100644
--- a/drivers/gpu/drm/i915/i915_pci.c
+++ b/drivers/gpu/drm/i915/i915_pci.c
@@ -538,7 +538,7 @@ static const struct intel_device_info vlv_info = {
 	.cpu_transcoder_mask = BIT(TRANSCODER_A) | BIT(TRANSCODER_B) | \
 		BIT(TRANSCODER_C) | BIT(TRANSCODER_EDP), \
 	.display.has_ddi = 1, \
-	.has_fpga_dbg = 1, \
+	.display.has_fpga_dbg = 1, \
 	.display.has_psr = 1, \
 	.display.has_psr_hw_tracking = 1, \
 	.display.has_dp_mst = 1, \
@@ -689,7 +689,7 @@ static const struct intel_device_info skl_gt4_info = {
 		BIT(TRANSCODER_DSI_A) | BIT(TRANSCODER_DSI_C), \
 	.has_64bit_reloc = 1, \
 	.display.has_ddi = 1, \
-	.has_fpga_dbg = 1, \
+	.display.has_fpga_dbg = 1, \
 	.display.has_fbc = 1, \
 	.display.has_hdcp = 1, \
 	.display.has_psr = 1, \
diff --git a/drivers/gpu/drm/i915/intel_device_info.h b/drivers/gpu/drm/i915/intel_device_info.h
index e6ca1023ffcf..d44f64b57b7a 100644
--- a/drivers/gpu/drm/i915/intel_device_info.h
+++ b/drivers/gpu/drm/i915/intel_device_info.h
@@ -118,7 +118,6 @@ enum intel_ppgtt_type {
 	func(has_64bit_reloc); \
 	func(gpu_reset_clobbers_display); \
 	func(has_reset_engine); \
-	func(has_fpga_dbg); \
 	func(has_global_mocs); \
 	func(has_gt_uc); \
 	func(has_l3_dpf); \
@@ -145,6 +144,7 @@ enum intel_ppgtt_type {
 	func(has_dsb); \
 	func(has_dsc); \
 	func(has_fbc); \
+	func(has_fpga_dbg); \
 	func(has_gmch); \
 	func(has_hdcp); \
 	func(has_hotplug); \
-- 
2.25.4

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