echo 3 >> /sys/class/graphics/fbcon/rotate_all, then switch to another
console. Result:

BUG: unable to handle kernel paging request at ffffc20005d00000
IP: [bitfill_aligned+149/265] bitfill_aligned+0x95/0x109
PGD 7e228067 PUD 7e229067 PMD 7bc1f067 PTE 0
Oops: 0002 [1] SMP
CPU 1
Modules linked in: [...a lot...]
Pid: 10, comm: events/1 Not tainted 2.6.26.5-45.fc9.x86_64 #1
RIP: 0010:[bitfill_aligned+149/265] [bitfill_aligned+149/265] bitfill_aligned+0x95/0x109
RSP: 0018:ffff81007d811bc8 EFLAGS: 00010216
RAX: ffffc20005d00000 RBX: 0000000000000000 RCX: 0000000000000400
RDX: 0000000000000000 RSI: ffffc20005d00000 RDI: ffffffffffffffff
RBP: ffff81007d811be0 R08: 0000000000000400 R09: 0000000000000040
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000010000
R13: ffffffff811632f0 R14: 0000000000000006 R15: ffff81007cb85400
FS: 0000000000000000(0000) GS:ffff81007e004780(0000) knlGS:0000000000000000
CS: 0010 DS: 0018 ES: 0018 CR0: 000000008005003b
CR2: ffffc20005d00000 CR3: 0000000000201000 CR4: 00000000000006e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Process events/1 (pid: 10, threadinfo ffff81007d810000, task ffff81007d808000)
Stack: ffff81007c9d75a0 0000000000000000 0000000000000000 ffff81007d811c80
ffffffff81163a61 ffff810000000000 ffffffff8115f9c8 0000001000000000
0000000100aaaaaa 000000007cd0d4a0 fffffd8a00000800 0001000000000000
Call Trace:
[cfb_fillrect+523/798] cfb_fillrect+0x20b/0x31e
[soft_cursor+416/436] ? soft_cursor+0x1a0/0x1b4
[ccw_clear_margins+205/263] ccw_clear_margins+0xcd/0x107
[fbcon_clear_margins+59/61] fbcon_clear_margins+0x3b/0x3d
[fbcon_switch+1291/1466] fbcon_switch+0x50b/0x5ba
[redraw_screen+261/481] redraw_screen+0x105/0x1e1
[ccw_cursor+0/1869] ? ccw_cursor+0x0/0x74d
[complete_change_console+48/190] complete_change_console+0x30/0xbe
[change_console+115/120] change_console+0x73/0x78
[console_callback+0/292] ? console_callback+0x0/0x124
[console_callback+97/292] console_callback+0x61/0x124
[schedule_delayed_work+25/30] ? schedule_delayed_work+0x19/0x1e
[run_workqueue+139/282] run_workqueue+0x8b/0x11a
[worker_thread+221/238] worker_thread+0xdd/0xee
[autoremove_wake_function+0/56] ? autoremove_wake_function+0x0/0x38
[worker_thread+0/238] ? worker_thread+0x0/0xee
[kthread+73/118] kthread+0x49/0x76
[child_rip+10/18] child_rip+0xa/0x12
[kthread+0/118] ? kthread+0x0/0x76
[child_rip+0/18] ? child_rip+0x0/0x12

Because fbcon_set_all_vcs()->FBCON_SWAP() uses display->rotate == 0 instead
of fbcon_ops->rotate, and vc_resize() has no effect because it is called with
new_cols/rows == ->vc_cols/rows.

Tested on 2.6.26.5-45.fc9.x86_64, but
http://git.kernel.org/?p=linux/kerne.../linux-2.6.git seems to
have the same problem.

Signed-off-by: Oleg Nesterov

--- linux-2.6.26.x86_64/drivers/video/console/fbcon.c~FBROT_FIX 2008-10-13 14:05:17.000000000 +0200
+++ linux-2.6.26.x86_64/drivers/video/console/fbcon.c 2008-10-13 14:07:36.000000000 +0200
@@ -2990,8 +2990,8 @@ static void fbcon_set_all_vcs(struct fb_
p = &fb_display[vc->vc_num];
set_blitting_type(vc, info);
var_to_display(p, &info->var, info);
- cols = FBCON_SWAP(p->rotate, info->var.xres, info->var.yres);
- rows = FBCON_SWAP(p->rotate, info->var.yres, info->var.xres);
+ cols = FBCON_SWAP(ops->rotate, info->var.xres, info->var.yres);
+ rows = FBCON_SWAP(ops->rotate, info->var.yres, info->var.xres);
cols /= vc->vc_font.width;
rows /= vc->vc_font.height;
vc_resize(vc, cols, rows);

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