Thread (18 messages) 18 messages, 4 authors, 2017-03-18
STALE3376d
Revisions (5)
  1. v2 [diff vs current]
  2. v3 [diff vs current]
  3. v4 [diff vs current]
  4. v4 current
  5. v4 [diff vs current]

[PATCH 2/4] qxl: limit monitor config read retries

From: Gerd Hoffmann <kraxel@redhat.com>
Date: 2017-03-08 09:20:30
Also in: dri-devel, linux-arm-kernel, linux-mmc, lkml
Subsystem: drm driver for qxl virtual gpu, drm drivers, drm drivers and misc gpu patches, the rest · Maintainers: Dave Airlie, Gerd Hoffmann, David Airlie, Simona Vetter, Maarten Lankhorst, Maxime Ripard, Thomas Zimmermann, Linus Torvalds

When reading the monitor config fails, don't retry forever.  If it fails
ten times in a row just give up to avoid the driver hangs.  Also add a
small delay after each attempt, so the host has a chance to complete a
partial update.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
---
 drivers/gpu/drm/qxl/qxl_display.c | 20 ++++++++++++--------
 1 file changed, 12 insertions(+), 8 deletions(-)
diff --git a/drivers/gpu/drm/qxl/qxl_display.c b/drivers/gpu/drm/qxl/qxl_display.c
index 2cd14be..2b99496 100644
--- a/drivers/gpu/drm/qxl/qxl_display.c
+++ b/drivers/gpu/drm/qxl/qxl_display.c
@@ -157,19 +157,23 @@ static void qxl_update_offset_props(struct qxl_device *qdev)
 
 void qxl_display_read_client_monitors_config(struct qxl_device *qdev)
 {
-
 	struct drm_device *dev = &qdev->ddev;
-	int status;
+	int status, retries;
 
-	status = qxl_display_copy_rom_client_monitors_config(qdev);
-	while (status == MONITORS_CONFIG_BAD_CRC) {
-		qxl_io_log(qdev, "failed crc check for client_monitors_config,"
-				 " retrying\n");
+	for (retries = 0; retries < 10; retries++) {
 		status = qxl_display_copy_rom_client_monitors_config(qdev);
+		if (status != MONITORS_CONFIG_BAD_CRC)
+			break;
+		udelay(5);
+	}
+	if (status == MONITORS_CONFIG_BAD_CRC) {
+		qxl_io_log(qdev, "config: bad crc\n");
+		DRM_DEBUG_KMS("ignoring client monitors config: bad crc");
+		return;
 	}
 	if (status == MONITORS_CONFIG_UNCHANGED) {
-		qxl_io_log(qdev, "config unchanged\n");
-		DRM_DEBUG("ignoring unchanged client monitors config");
+		qxl_io_log(qdev, "config: unchanged\n");
+		DRM_DEBUG_KMS("ignoring client monitors config: unchanged");
 		return;
 	}
 
-- 
1.8.3.1

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