Re: [PATCH] vgacon.c: add cond reschedule points in vgacon_do_font_op

From: Dave Airlie
Date: Wed Jun 26 2013 - 02:37:04 EST


> can result in a soft lockup:
>
> BUG: soft lockup - CPU#41 stuck for 67s! [setfont:1505]
> RIP: 0010:[<ffffffff812c48da>]
> [<ffffffff812c48da>] vgacon_do_font_op.clone.0+0x1ba/0x550
>
> This is due to the 8192 (cmapsz) IO operations taking longer than expected
> due to lock contention in QEMU.
>
> Add conditional resched points in between writes allowing other tasks to
> execute.

I've applied this to drm-next against my best judgement as it steers
me close to being the console maintainer.

Dave.
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