On Fri, Mar 12, 2010 at 3:51 AM, Tomi Valkeinen
<tomi.valkeinen@xxxxxxxxx> wrote:
> Can you try this patch?
>
> I haven't run into this earlier as I always have DSI compiled in. It
> possibly doesn't behave correctly in that case either, but doesn't
> crash.
Sorry, I got side-tracked with some unrelated client work.
I finally tried the patch this morning and it does fix the issue.
Thanks!
Steve
> Tomi
>
>
> >From c065bb82e1358105d57d80974ce71d3e5aeabf35 Mon Sep 17 00:00:00 2001
> From: Tomi Valkeinen <tomi.valkeinen@xxxxxxxxx>
> Date: Fri, 12 Mar 2010 12:46:05 +0200
> Subject: [PATCH] OMAP: DSS2: initialize dss clk sources properly
>
> Clk sources were not initialized, leading to kernel crash, or possibly to
> strange behaviour if DSI was compiled in.
>
> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@xxxxxxxxx>
> ---
> drivers/video/omap2/dss/dss.c | 3 +++
> 1 files changed, 3 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/video/omap2/dss/dss.c b/drivers/video/omap2/dss/dss.c
> index 8254a42..5434418 100644
> --- a/drivers/video/omap2/dss/dss.c
> +++ b/drivers/video/omap2/dss/dss.c
> @@ -590,6 +590,9 @@ int dss_init(bool skip_init)
> }
> }
>
> + dss.dsi_clk_source = DSS_SRC_DSS1_ALWON_FCLK;
> + dss.dispc_clk_source = DSS_SRC_DSS1_ALWON_FCLK;
> +
> dss_save_context();
>
> rev = dss_read_reg(DSS_REVISION);
> --
> 1.6.5
>
>
>
>
>
>
> On Wed, 2010-03-10 at 20:48 +0100, ext Steve Sakoman wrote:
>> On Wed, Mar 10, 2010 at 10:58 AM, <Tomi.Valkeinen@xxxxxxxxx> wrote:
>>
>> > I haven't had time to look at this, but I don't think your analysis is correct.
>>
>> You are correct of course. My sleepy eyes neglected to notice that
>> double = and that makes a big difference :-)
>>
>> > What first comes to my mind is that dss.dispc_clk_source is, for some reason, uninitialized. Could you put prints to dss_select_dispc_clk_source to see if it's called, and if so, what is assigned to dss.dispc_clk_source?
>>
>> I did a build with that change and it does seem that
>> dss_select_dispc_clk_source is never called.
>>
>> Steve
>>
>> > Tomi
>> >
>> > ________________________________________
>> > From: ext Steve Sakoman [sakoman@xxxxxxxxx]
>> > Sent: Wednesday, March 10, 2010 20:42
>> > To: linux-omap@xxxxxxxxxxxxxxx; Valkeinen Tomi (Nokia-D/Helsinki)
>> > Subject: Re: kernel panic with latest DSS
>> >
>> > On Wed, Mar 10, 2010 at 10:16 AM, Steve Sakoman <sakoman@xxxxxxxxx> wrote:
>> >
>> >> The issue occurs in the following section of code in
>> >> drivers/video/omap2/dss/dispc.c:
>> >>
>> >> unsigned long dispc_fclk_rate(void)
>> >> {
>> >> unsigned long r = 0;
>> >>
>> >> if (dss_get_dispc_clk_source() == DSS_SRC_DSS1_ALWON_FCLK)
>> >> r = dss_clk_get_rate(DSS_CLK_FCK1);
>> >> else
>> >> #ifdef CONFIG_OMAP2_DSS_DSI
>> >> r = dsi_get_dsi1_pll_rate();
>> >> #else
>> >> BUG();
>> >> #endif
>> >> return r;
>> >> }
>> >>
>> >> Since my machines don't have DSI displays CONFIG_OMAP2_DSS_DSI is not
>> >> defined and the BUG() call is triggered.
>> >
>> > The issue seems to be the test for DSS_SRC_DSS1_ALWON_FCLK.
>> >
>> > Looking at drivers/video/omap2/dss/dispc.c I see that
>> > DSS_SRC_DSS1_ALWON_FCLK will never be returned since clk_src is always
>> > set to 0 or 1 based on a test of DSS_SRC_DSS1_ALWON_FCLK :
>> >
>> > void dss_select_dispc_clk_source(enum dss_clk_source clk_src)
>> > {
>> > int b;
>> >
>> > BUG_ON(clk_src != DSS_SRC_DSI1_PLL_FCLK &&
>> > clk_src != DSS_SRC_DSS1_ALWON_FCLK);
>> >
>> > b = clk_src == DSS_SRC_DSS1_ALWON_FCLK ? 0 : 1;
>> >
>> > REG_FLD_MOD(DSS_CONTROL, b, 0, 0); /* DISPC_CLK_SWITCH */
>> >
>> > dss.dispc_clk_source = clk_src;
>> > }
>> >
>> > It seems to me that the test should return to the way it was in the
>> > previous DSS version, i.e. a test for 0:
>> >
>> > diff --git a/drivers/video/omap2/dss/dispc.c b/drivers/video/omap2/dss/dispc.c
>> > index e777e35..be9b3de 100644
>> > --- a/drivers/video/omap2/dss/dispc.c
>> > +++ b/drivers/video/omap2/dss/dispc.c
>> > @@ -2218,7 +2218,7 @@ unsigned long dispc_fclk_rate(void)
>> > {
>> > unsigned long r = 0;
>> >
>> > - if (dss_get_dispc_clk_source() == DSS_SRC_DSS1_ALWON_FCLK)
>> > + if (dss_get_dispc_clk_source() == 0)
>> > r = dss_clk_get_rate(DSS_CLK_FCK1);
>> > else
>> > #ifdef CONFIG_OMAP2_DSS_DSI
>> >
>> > A test build confirms that this change restores my ability to play
>> > DVD's and display webcam streams. My understanding of this code is
>> > superficial, so hopefully Tomi can comment on whether this is a good
>> > fix or not.
>> >
>> > Steve
>
>
>
--
To unsubscribe from this list: send the line "unsubscribe linux-omap" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
