video: hyperv_fb: Add ratelimit on error message

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@microsoft.com>
Link: https://lore.kernel.org/r/1618933459-10585-1-git-send-email-mikelley@microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>

diff --git a/drivers/video/fbdev/hyperv_fb.c b/drivers/video/fbdev/hyperv_fb.c
index c8b0ae6..68adbf8 100644 (file)
--- a/drivers/video/fbdev/hyperv_fb.c
+++ b/drivers/video/fbdev/hyperv_fb.c
@@ -308,7 +308,7 @@ 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;
 }