linux-kernel - [PATCH 3/5] drm/komeda: Optionally dump DRM state on interrupts

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Date:   Mon, 21 Oct 2019 16:47:24 +0000
From:   Mihail Atanassov <Mihail.Atanassov@....com>
To:     "dri-devel@...ts.freedesktop.org" <dri-devel@...ts.freedesktop.org>
CC:     Mihail Atanassov <Mihail.Atanassov@....com>, nd <nd@....com>,
        Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
        Maxime Ripard <mripard@...nel.org>,
        Sean Paul <sean@...rly.run>, Liviu Dudau <Liviu.Dudau@....com>,
        Brian Starkey <Brian.Starkey@....com>,
        David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        "james qian wang (Arm Technology China)" <james.qian.wang@....com>,
        "Lowry Li (Arm Technology China)" <Lowry.Li@....com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: [PATCH 3/5] drm/komeda: Optionally dump DRM state on interrupts

It's potentially useful information when diagnosing error/warn IRQs, so
dump it to dmesg with a drm_info_printer. Hide this extra debug dumping
behind another komeda_dev->err_verbosity bit.

Note that there's not much sense in dumping it for INFO events,
since the VSYNC event will swamp the log.

Signed-off-by: Mihail Atanassov <mihail.atanassov@....com>
---
 drivers/gpu/drm/arm/display/komeda/komeda_dev.h   | 5 ++++-
 drivers/gpu/drm/arm/display/komeda/komeda_event.c | 8 +++++++-
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/arm/display/komeda/komeda_dev.h b/drivers/gpu/drm/arm/display/komeda/komeda_dev.h
index 831c375180f8..4809000c1efb 100644
--- a/drivers/gpu/drm/arm/display/komeda/komeda_dev.h
+++ b/drivers/gpu/drm/arm/display/komeda/komeda_dev.h
@@ -205,11 +205,14 @@ struct komeda_dev {
 	/**
 	 * @err_verbosity: bitmask for how much extra info to print on error
 	 *
-	 * See KOMEDA_DEV_* macros for details.
+	 * See KOMEDA_DEV_* macros for details. Low byte contains the debug
+	 * level categories, the high byte contains extra debug options.
 	 */
 	u16 err_verbosity;
 	/* Print a single line per error per frame with error events. */
 #define KOMEDA_DEV_PRINT_ERR_EVENTS BIT(0)
+	/* Dump DRM state on an error or warning event. */
+#define KOMEDA_DEV_PRINT_DUMP_STATE_ON_EVENT BIT(8)
 };
 
 static inline bool
diff --git a/drivers/gpu/drm/arm/display/komeda/komeda_event.c b/drivers/gpu/drm/arm/display/komeda/komeda_event.c
index 575ed4df74ed..5da61e7d75d5 100644
--- a/drivers/gpu/drm/arm/display/komeda/komeda_event.c
+++ b/drivers/gpu/drm/arm/display/komeda/komeda_event.c
@@ -4,6 +4,7 @@
  * Author: James.Qian.Wang <james.qian.wang@....com>
  *
  */
+#include <drm/drm_atomic.h>
 #include <drm/drm_print.h>
 
 #include "komeda_dev.h"
@@ -113,6 +114,7 @@ void komeda_print_events(struct komeda_events *evts, struct drm_device *dev)
 	static bool en_print = true;
 	struct komeda_dev *mdev = dev->dev_private;
 	u16 const err_verbosity = mdev->err_verbosity;
+	u64 evts_mask = evts->global | evts->pipes[0] | evts->pipes[1];
 
 	/* reduce the same msg print, only print the first evt for one frame */
 	if (evts->global || is_new_frame(evts))
@@ -123,9 +125,10 @@ void komeda_print_events(struct komeda_events *evts, struct drm_device *dev)
 	if (err_verbosity & KOMEDA_DEV_PRINT_ERR_EVENTS)
 		print_evts |= KOMEDA_ERR_EVENTS;
 
-	if ((evts->global | evts->pipes[0] | evts->pipes[1]) & print_evts) {
+	if (evts_mask & print_evts) {
 		char msg[256];
 		struct komeda_str str;
+		struct drm_printer p = drm_info_printer(dev->dev);
 
 		str.str = msg;
 		str.sz  = sizeof(msg);
@@ -139,6 +142,9 @@ void komeda_print_events(struct komeda_events *evts, struct drm_device *dev)
 		evt_str(&str, evts->pipes[1]);
 
 		DRM_ERROR("err detect: %s\n", msg);
+		if ((err_verbosity & KOMEDA_DEV_PRINT_DUMP_STATE_ON_EVENT)
+		    && (evts_mask & (KOMEDA_ERR_EVENTS | KOMEDA_WARN_EVENTS)))
+			drm_state_dump(dev, &p);
 
 		en_print = false;
 	}
-- 
2.23.0