Re: [PATCH] staging: irda: resolve sparse errors due to implicit pci_power_t casts

[Matthew Giassa]

* Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx> [2017-10-18 16:12:16 +0200]:

> On Thu, Oct 05, 2017 at 04:38:23PM -0700, Matthew Giassa wrote:
> > Explicitly casting pci_power_t types to resolve sparse warnings (shown
> > below).
> >
> > Also fixing a related logging bug where pci_power_t is cast to unsigned
> > (can be negative, i.e. PCI_POWER_ERROR).
> >
> > Original sparse report:
> >
> > drivers/staging/irda/drivers//vlsi_ir.c:170:51: warning: cast from
> > restricted pci_power_t
> > drivers/staging/irda/drivers//vlsi_ir.c:1726:39: warning: restricted
> > pci_power_t degrades to integer
> > drivers/staging/irda/drivers//vlsi_ir.c:1728:45: warning: incorrect type
> > in assignment (different base types)
> > drivers/staging/irda/drivers//vlsi_ir.c:1728:45:    expected restricted
> > pci_power_t [usertype] current_state
> > drivers/staging/irda/drivers//vlsi_ir.c:1728:45:    got int [signed]
> > [usertype] event
> > drivers/staging/irda/drivers//vlsi_ir.c:1748:29: warning: incorrect type
> > in assignment (different base types)
> > drivers/staging/irda/drivers//vlsi_ir.c:1748:29:    expected restricted
> > pci_power_t [usertype] current_state
> > drivers/staging/irda/drivers//vlsi_ir.c:1748:29:    got int [signed]
> > [usertype] event
>
> Please do not line-wrap lines like this, it makes them harder to
> understand.
Duly noted.

> > Warnings no longer present.
> >
> > Signed-off-by: Matthew Giassa <matthew@xxxxxxxxxx>
> > ---
> >  drivers/staging/irda/drivers/vlsi_ir.c | 10 ++++++----
> >  1 file changed, 6 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/staging/irda/drivers/vlsi_ir.c b/drivers/staging/irda/drivers/vlsi_ir.c
> > index 3dff3c5..20ce4d8 100644
> > --- a/drivers/staging/irda/drivers/vlsi_ir.c
> > +++ b/drivers/staging/irda/drivers/vlsi_ir.c
> > @@ -167,7 +167,8 @@ static void vlsi_proc_pdev(struct seq_file *seq, struct pci_dev *pdev)
> >
> >  	seq_printf(seq, "\n%s (vid/did: [%04x:%04x])\n",
> >  		   pci_name(pdev), (int)pdev->vendor, (int)pdev->device);
> > -	seq_printf(seq, "pci-power-state: %u\n", (unsigned) pdev->current_state);
> > +	seq_printf(seq, "pci-power-state: %d\n",
> > +		   (int __force)pdev->current_state);
>
> Ick, using __force is almost always a huge sign that something is wrong
> here.  This patch does not look correct because of this.
>
> You did read drivers/staging/irda/TODO, right?
>
> thanks,
>
> greg k-h

Good point. This patch can be discarded.

-Matthew