Re: [PATCH v1 41/63] Input: touchscreen: Atmel: Enable IRQ_DISABLE_UNLAZY flag for interrupt

[Jiada Wang]

Hi Dmitry

On 2019/08/17 2:26, Dmitry Torokhov wrote:
> On Fri, Aug 16, 2019 at 05:35:36PM +0900, Jiada Wang wrote:
> > From: Bhuvanesh Surachari <bhuvanesh_surachari@xxxxxxxxxx>
> >
> > The de-/serializer driver has defined only irq_mask "ds90ub927_irq_mask" and
> > irq_unmask "ds90ub927_irq_unmask" callback functions. And de-/serializer
> > driver doesn't implement the irq_disable and irq_enable callback functions.
> > Hence inorder to invoke irq_mask callback function when disable_irq_nosync is
> > called the IRQ_DISABLE_UNLAZY interrupt flag should be set. If not the
> > disable_irq_nosync will just increment the depth field in the irq
> > descriptor only once as shown below.
> >
> > disable_irq_nosync
> >   __disable_irq_nosync
> >    __disable_irq (desc->depth++)
> >     irq_disable
> >      if irq_disable present -----------> if IRQ_DISABLE_UNLAZYflag set
> >               |                  no                  |
> >           yes |                                  yes |
> >               |                                      |
> >       desc->irq_data.chip->irq_disable   desc->irq_data.chip->irq_unmask
> >                                           (ds90ub927_irq_mask)
> >                                            disable_irq
> >                                             __disable_irq_nosync
> >                                              __disable_irq
> > (desc->depth++)
> > But the enable_irq will try to decrement the depth field twice which generates
> > the backtrace stating "Unbalanced enable for irq 293". This is because there is
> > no IRQ_DISABLE_UNLAZY flag check while calling irq_unmask callback function
> > of the "ds90ub927_irq_unmask" de-/serializer via enable_irq.
> >
> > enable_irq
> >   __enable_irq (desc->depth--)
> >    irq_enable
> >     if irq_enable present -------------> desc->irq_data.chip->irq_unmask
> >                |                no        (ds90ub927_irq_unmask)
> >            yes |                            enable_irq
> >                |                             __enable_irq (desc->depth--)
> >      (desc->irq_data.chip->irq_enable)
>
> I'd prefer if we instead did not use the disable_irq_nosync() in the
> driver.
sorry for the mistake, during forward port,
I have already eliminated disable_irq_nosync(),
so this patch is no longer needed,
will drop it in v2 patch-set

Thanksï
Jiada

> Thanks.