Re: [PATCH] clocksource: sh_tmu: Set cpu_possible_mask to fix SMP broadcast

[Geert Uytterhoeven]

Hi Laurent, Magnus,

On Wed, Dec 17, 2014 at 9:30 AM, Geert Uytterhoeven
<geert@xxxxxxxxxxxxxx> wrote:
> On Wed, Dec 17, 2014 at 3:08 AM, Laurent Pinchart
> <laurent.pinchart@xxxxxxxxxxxxxxxx> wrote:
>>> > Kzm9g-reference still hangs at "Calibrating local timer..." (it did work
>>> > at some point in the past).
>>
>> kzm9g-reference boots for me with kzm9g_defconfig on Simon's devel branch with
>
> OK.
>
> I had expected the breakage to be something in my tree, either an issue in
> a -next branch I'm using, an interaction with the CCF patches or so, or a
> config issue (e.g. CONFIG_CPU_IDLE became broken lately if the TWD is
> not in DT).

Kzm9g-reference hangs at "Calibrating local timer..." because I added the
TWD to sh73a0.dtsi (http://www.spinics.net/lists/arm-kernel/msg383413.html).

As twd_get_clock() does

        if (np)
                twd_clk = of_clk_get(np, 0);
        else
                twd_clk = clk_get_sys("smp_twd", NULL);

it's not DT-without-CCF proof, and kzm9g-reference cannot get its clock :-(

So the TWD node should be in sh73a0-kzm9g-multiplatform.dts, and we need
more dts files instead of less...

Note that I added the TWD node to DT to fix a hang on kzm9g-multiplatform
with CONFIG_CPU_IDLE=y (recently introduced "regression" in core code) after:

     DMA: preallocated 256 KiB pool for atomic coherent allocations

On kzm9g-legacy the TWD is instantiated from C board code
(machine_desc.init_time = sh73a0_earlytimer_init), so CONFIG_CPU_IDLE=y
does not hang. Despite https://lkml.org/lkml/2014/12/2/339.

On kzm9g-reference, the TWD is not instantiated, causing the same hang.
If I instantiate the TWD from C board code there, it fails with

    twd: can't register interrupt 29 (-22)

which looks like a symptom of https://lkml.org/lkml/2014/12/2/339

So no cookies for users of several -legacy and -reference platforms in v3.19-rc1
this Monday...

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds
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