[PATCH] fbcon: warn on invalid cursor blink intervals

Scot Doyle
2016-05-19T22:31:49Z

Two systems are locking on boot [1] because ops->cur_blink_jiffies
is set to zero from vc->vc_cur_blink_ms.

Ignore such invalid intervals and log a warning.

[1] https://bugs.launchpad.net/bugs/1574814

Suggested-by: David Daney <david.daney@cavium.com>
Signed-off-by: Scot Doyle <lkml14@scotdoyle.com>
Cc: <stable@vger.kernel.org> [v4.2]
---
drivers/video/console/fbcon.c | 14 ++++++++++++--
1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/drivers/video/console/fbcon.c b/drivers/video/console/fbcon.c
index 6e92917..fad5b89 100644
--- a/drivers/video/console/fbcon.c
+++ b/drivers/video/console/fbcon.c
@@ -1095,7 +1095,13 @@ static void fbcon_init(struct vc_data *vc, int init)
con_copy_unimap(vc, svc);

ops = info->fbcon_par;
- ops->cur_blink_jiffies = msecs_to_jiffies(vc->vc_cur_blink_ms);
+
+ if (vc->vc_cur_blink_ms >= 50)
+ ops->cur_blink_jiffies =
+ msecs_to_jiffies(vc->vc_cur_blink_ms);
+ else
+ WARN_ONCE(1, "blink interval < 50 ms");
+
p->con_rotate = initial_rotation;
set_blitting_type(vc, info);

@@ -1309,7 +1315,11 @@ static void fbcon_cursor(struct vc_data *vc, int mode)
int y;
int c = scr_readw((u16 *) vc->vc_pos);

- ops->cur_blink_jiffies = msecs_to_jiffies(vc->vc_cur_blink_ms);
+ if (vc->vc_cur_blink_ms >= 50)
+ ops->cur_blink_jiffies =
+ msecs_to_jiffies(vc->vc_cur_blink_ms);
+ else
+ WARN_ONCE(1, "blink interval < 50 ms");

if (fbcon_is_inactive(vc, info) || vc->vc_deccm != 1)
return;
--
2.1.4