lkml.org 
[lkml]   [2017]   [Oct]   [19]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH v2] clk: tegra: Use readl_relaxed_poll_timeout_atomic in tegra210_clock_init
On Thu, Oct 19, 2017 at 11:44:22AM +0200, Thierry Reding wrote:
> > > Below is the call trace of tegra210_init_pllu() function:
> > > start_kernel()
> > > -> time_init()
> > > --> of_clk_init()
> > > ---> tegra210_clock_init()
> > > ----> tegra210_pll_init()
> > > -----> tegra210_init_pllu()

> I'm wondering why we're not seeing a splat for this. Usually the kernel
> will warn if you sleep during atomic context. Does this mean we're just
> not hitting that case?

Yes.

> readx_poll_timeout() has a might_sleep_if(), and
> therefore it should always cause the splat.

That's true as long as CONFIG_DEBUG_ATOMIC_SLEEP is enabled locally.

> Any ideas why this has gone unnoticed for all this time?

We can see in the tegra210_init_pllu() function that it'll not call
tegra210_enable_pllu() if pllu is already enabled (by bootloader).

You can verify it by adding an irqs_disabled() in this routine. The
function is called during system-boot and suspend-n-resume. And both
cases should be irqs_disabled().

Thanks
Nicolin

\
 
 \ /
  Last update: 2017-10-22 17:29    [W:0.100 / U:0.196 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site