On Tue, May 19, 2015 at 02:15:41PM -0700, Kevin Hilman wrote:

On Thu, Mar 26, 2015 at 6:56 AM, Scot Doyle [off-list ref] wrote:

quoted

vt now provides a cursor blink interval via vc_data. Use this
interval instead of the currently hardcoded 200 msecs. Store it in
fbcon_ops to avoid locking the console in cursor_timer_handler().

Signed-off-by: Scot Doyle <redacted>
Acked-by: Pavel Machek <redacted>

This patch hit next-20150519 in the form of commit 27a4c827c34a
(fbcon: use the cursor blink interval provided by vt) and has caused
boot failure on a handful of ARM platforms when booting a MMC root
filesystem.  This error was spotted by the kernelci.org bot on
exynos5800-peach-pi[1] and Thierry and Daniel (Cc'd) have seen it on
some tegra platforms too.

Thierry spotted this commit as a potential cause, and both Daniel and
I have reverted and boot tested on exynos5 and tegra respectively and
the boot panics disappear.

FWIW, if I apply the below on top of next-20150519 things seem to be
back to normal as well:

diff --git a/drivers/video/console/fbcon.c b/drivers/video/console/fbcon.c
index 05b1d1a71ef9..658c34bb9076 100644
--- a/drivers/video/console/fbcon.c
+++ b/drivers/video/console/fbcon.c

@@ -1310,8 +1310,9 @@ static void fbcon_cursor(struct vc_data *vc, int mode)
                return;
 
        ops->cur_blink_jiffies = msecs_to_jiffies(vc->vc_cur_blink_ms);
-       fbcon_del_cursor_timer(info);
-       if (!(vc->vc_cursor_type & 0x10))
+       if (vc->vc_cursor_type & 0x10)
+               fbcon_del_cursor_timer(info);
+       else
                fbcon_add_cursor_timer(info);
 
        ops->cursor_flash = (mode == CM_ERASE) ? 0 : 1;