Hello Jerome,
Thank you for the review!
On Tue, Jul 04, 2023 at 09:43:41PM +0200, Jerome Brunet wrote:
>
> On Mon 03 Jul 2023 at 23:04, Dmitry Rokosov <ddrokosov@xxxxxxxxxxxxxx> wrote:
>
> > The function meson_clk_pll_enable() can be invoked under the enable_lock
> > spinlock from the clk core logic
>
> ---
> > (please refer to
> > drivers/clk/clk.c:clk_core_enable_lock()), which risks a kernel panic
> > during the usleep_range() call:
> >
>
> This part of the comment is not very useful - please drop it
>
Do you mean a stack trace or reference to clk_core_enable_lock()?
> > BUG: scheduling while atomic: kworker/u4:2/36/0x00000002
> > Modules linked in: g_ffs usb_f_fs libcomposite
> > CPU: 1 PID: 36 Comm: kworker/u4:2 Not tainted 6.4.0-rc5 #273
> > Workqueue: events_unbound async_run_entry_fn
> > Call trace:
> > dump_backtrace+0x9c/0x128
> > show_stack+0x20/0x38
> > dump_stack_lvl+0x48/0x60
> > dump_stack+0x18/0x28
> > __schedule_bug+0x58/0x78
> > __schedule+0x828/0xa88
> > schedule+0x64/0xd8
> > schedule_hrtimeout_range_clock+0xd0/0x208
> > schedule_hrtimeout_range+0x1c/0x30
> > usleep_range_state+0x6c/0xa8
> > meson_clk_pll_enable+0x1f4/0x310
> > clk_core_enable+0x78/0x200
> > clk_core_enable+0x58/0x200
> > clk_core_enable+0x58/0x200
> > clk_core_enable+0x58/0x200
> > clk_enable+0x34/0x60
> >
> > Considering that this code is expected to be used in an atomic context,
> > it is required to use the udelay() function instead of usleep_range()
> > for the atomic context safety.
>
> Please use an imperative form, instructing the code to change
>
Ack
> >
> > Fixes: b6ec400aa153 ("clk: meson: introduce new pll power-on sequence for A1 SoC family")
> > Reported-by: Jan Dakinevich <yvdakinevich@xxxxxxxxxxxxxx>
> > Signed-off-by: Dmitry Rokosov <ddrokosov@xxxxxxxxxxxxxx>
> > Signed-off-by: Jan Dakinevich <yvdakinevich@xxxxxxxxxxxxxx>
>
> The tags are confusing here
> I suppose a 2 lines change has not be been written with 4 hands ;)
>
> If Jan just reported and you made the change then drop his signed-off
> If he did the job, then drop the reported-by and change the author
>
No problem :) Sometimes 2 lines change is produced during 4 hands
debugging :)
> > ---
> > drivers/clk/meson/clk-pll.c | 4 ++--
> > 1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/clk/meson/clk-pll.c b/drivers/clk/meson/clk-pll.c
> > index 56ec2210f1ad..eef6f37c8d8d 100644
> > --- a/drivers/clk/meson/clk-pll.c
> > +++ b/drivers/clk/meson/clk-pll.c
> > @@ -367,9 +367,9 @@ static int meson_clk_pll_enable(struct clk_hw *hw)
> > * 3. enable the lock detect module
> > */
> > if (MESON_PARM_APPLICABLE(&pll->current_en)) {
> > - usleep_range(10, 20);
> > + udelay(10);
> > meson_parm_write(clk->map, &pll->current_en, 1);
> > - usleep_range(40, 50);
> > + udelay(40);
> > };
> >
> > if (MESON_PARM_APPLICABLE(&pll->l_detect)) {
>
--
Thank you,
Dmitry
