Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1352406

[PATCH 4.4 12/74] fbcon: set a default value to blink interval

Show all headers | View raw

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Jean-Philippe Brucker <jean-philippe.brucker@arm.com>

commit a1e533ec07d583d01349ef13c0c965b8633e1b91 upstream.

Since commit 27a4c827c34ac4256a190cc9d24607f953c1c459
	fbcon: use the cursor blink interval provided by vt

two attempts have been made at fixing a possible hang caused by
cursor_timer_handler. That function registers a timer to be triggered at
"jiffies + fbcon_ops.cur_blink_jiffies".

A new case had been encountered during initialisation of clcd-pl11x:

    fbcon_fb_registered
    do_fbcon_takeover

    ->  do_register_con_driver
        fbcon_startup
    (A) add_cursor_timer (with cur_blink_jiffies = 0)

    ->  do_bind_con_driver
        visual_init
        fbcon_init
    (B) cur_blink_jiffies = msecs_to_jiffies(vc->vc_cur_blink_ms);

If we take an softirq anywhere between A and B (and we do),
cursor_timer_handler executes indefinitely.

Instead of patching all possible paths that lead to this case one at a
time, fix the issue at the source and initialise cur_blink_jiffies to
200ms when allocating fbcon_ops. This was its default value before
aforesaid commit. fbcon_cursor or fbcon_init will refine this value
downstream.

Signed-off-by: Jean-Philippe Brucker <jean-philippe.brucker@arm.com>
Tested-by: Scot Doyle <lkml14@scotdoyle.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/video/console/fbcon.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/drivers/video/console/fbcon.c
+++ b/drivers/video/console/fbcon.c
@@ -709,6 +709,7 @@ static int con2fb_acquire_newinfo(struct
 	}
 
 	if (!err) {
+		ops->cur_blink_jiffies = HZ / 5;
 		info->fbcon_par = ops;
 
 		if (vc)
@@ -956,6 +957,7 @@ static const char *fbcon_startup(void)
 	ops->currcon = -1;
 	ops->graphics = 1;
 	ops->cur_rotate = -1;
+	ops->cur_blink_jiffies = HZ / 5;
 	info->fbcon_par = ops;
 	p->con_rotate = initial_rotation;
 	set_blitting_type(vc, info);

Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

[PATCH 4.4 00/74] 4.4.5-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-03-08 01:30 +0100
  [PATCH 4.4 09/74] parisc: Fix ptrace syscall number and return value modification Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-03-08 01:30 +0100
  [PATCH 4.4 18/74] arm/arm64: KVM: Fix ioctl error handling Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-03-08 01:30 +0100
  [PATCH 4.4 10/74] mips/kvm: fix ioctl error handling Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-03-08 01:30 +0100
  [PATCH 4.4 12/74] fbcon: set a default value to blink interval Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-03-08 01:30 +0100
  [PATCH 4.4 03/74] Btrfs: fix deadlock running delayed iputs at transaction commit time Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-03-08 01:30 +0100
  [PATCH 4.4 07/74] block: Initialize max_dev_sectors to 0 Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-03-08 01:30 +0100
  [PATCH 4.4 16/74] vfio: fix ioctl error handling Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-03-08 01:30 +0100
  Re: [PATCH 4.4 00/74] 4.4.5-stable review Guenter Roeck <linux@roeck-us.net> - 2016-03-08 12:50 +0100
    Re: [PATCH 4.4 00/74] 4.4.5-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-03-08 15:20 +0100
  Re: [PATCH 4.4 00/74] 4.4.5-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-03-08 15:40 +0100
    Re: [PATCH 4.4 00/74] 4.4.5-stable review Kevin Hilman <khilman@baylibre.com> - 2016-03-09 06:40 +0100
  Re: [PATCH 4.4 00/74] 4.4.5-stable review Shuah Khan <shuahkh@osg.samsung.com> - 2016-03-08 17:30 +0100
    Re: [PATCH 4.4 00/74] 4.4.5-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-03-09 03:10 +0100

csiph-web