linux-kernel - Re: [PATCH] fbcon: use default if cursor blink interval is not valid

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Date:	Thu, 19 May 2016 11:01:39 +0200
From:	Pavel Machek <pavel@....cz>
To:	Scot Doyle <lkml14@...tdoyle.com>
Cc:	Tomi Valkeinen <tomi.valkeinen@...com>,
	Jean-Christophe Plagniol-Villard <plagnioj@...osoft.com>,
	David Daney <david.daney@...ium.com>,
	Ming Lei <ming.lei@...onical.com>,
	Dann Frazier <dann.frazier@...onical.com>,
	Peter Hurley <peter@...leysoftware.com>,
	Jonathan Liu <net147@...il.com>,
	Alistair Popple <alistair@...ple.id.au>,
	Jean-Philippe Brucker <jean-philippe.brucker@....com>,
	"Chintakuntla, Radha" <Radha.Chintakuntla@...iumnetworks.com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Jiri Slaby <jslaby@...e.com>, David Airlie <airlied@...ux.ie>,
	ddaney.cavm@...il.com, dri-devel@...ts.freedesktop.org,
	linux-fbdev@...r.kernel.org, linux-kernel@...r.kernel.org,
	stable@...r.kernel.org
Subject: Re: [PATCH] fbcon: use default if cursor blink interval is not valid

Hi!

> Two current [1] and three previous [2] systems locked during boot
> because the cursor flash timer was set using an ops->cur_blink_jiffies
> value of 0. Previous patches attempted to solve the problem by moving
> variable initialization earlier in the setup sequence [2].
> 
> Use the normal cursor blink default interval of 200 ms if
> ops->cur_blink_jiffies is not in the range specified in commit
> bd63364caa8d. Since invalid values are not used, specific system
> initialization timings should not cause lockups.
> 
> [1] https://bugs.launchpad.net/bugs/1574814
> [2] see commits: 2a17d7e80f1d, f235f664a8af, a1e533ec07d5

Acked-by: Pavel Machek <pavel@....cz>

>  static void cursor_timer_handler(unsigned long dev_addr)
>  {
>  	struct fb_info *info = (struct fb_info *) dev_addr;
>  	struct fbcon_ops *ops = info->fbcon_par;
>  
>  	queue_work(system_power_efficient_wq, &info->queue);
> -	mod_timer(&ops->cursor_timer, jiffies + ops->cur_blink_jiffies);
> +	mod_timer(&ops->cursor_timer, jiffies +
> +	    cursor_blink_jiffies(ops->cur_blink_jiffies));
>  }
>  
>  static void fbcon_add_cursor_timer(struct fb_info *info)

And actually... perhaps mod_timer should have some check for too low
timeouts..?

WARN_ON?
									Pavel

-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html