[PATCH 1/3] video: hyperv_fb: Add ratelimit on error message

[Tim Gardner]

From: Michael Kelley <mikelley at microsoft.com>

BugLink: https://bugs.launchpad.net/bugs/1927518

Due to a full ring buffer, the driver may be unable to send updates to
the Hyper-V host.  But outputing the error message can make the problem
worse because console output is also typically written to the frame
buffer.  As a result, in some circumstances the error message is output
continuously.

Break the cycle by rate limiting the error message.  Also output
the error code for additional diagnosability.

Signed-off-by: Michael Kelley <mikelley at microsoft.com>
Link: https://lore.kernel.org/r/1618933459-10585-1-git-send-email-mikelley@microsoft.com
Signed-off-by: Wei Liu <wei.liu at kernel.org>
(cherry picked from commit aa5b7d11c7cb87c266d705b237368985e7171958)
Signed-off-by: Tim Gardner <tim.gardner at canonical.com>
---
 drivers/video/fbdev/hyperv_fb.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/video/fbdev/hyperv_fb.c b/drivers/video/fbdev/hyperv_fb.c
index 6e680007cf6b0..b63c0d7fd27f2 100644
--- a/drivers/video/fbdev/hyperv_fb.c
+++ b/drivers/video/fbdev/hyperv_fb.c
@@ -252,7 +252,7 @@ static inline int synthvid_send(struct hv_device *hdev,
 			       VM_PKT_DATA_INBAND, 0);
 
 	if (ret)
-		pr_err("Unable to send packet via vmbus\n");
+		pr_err_ratelimited("Unable to send packet via vmbus; error %d\n", ret);
 
 	return ret;
 }
-- 
2.17.1