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SubjectRe: [PATCH 1/2 v2] Driver for Freescale 8610 and 5121 DIU
On Fri, 21 Mar 2008 11:12:30 -0500 Timur Tabi <timur@freescale.com> wrote:

> Andrew Morton wrote:
>
> >> +static struct diu_hw dr = {
> >> + .mode = MFB_MODE1,
> >> + .reg_lock = __SPIN_LOCK_UNLOCKED(old_style_spin_init),
> >> +};
> >
> > I'm not clear on what's supposed to happen with __SPIN_LOCK_UNLOCKED(). I
> > do know that its documentation is crap.
>
> Yes, "__SPIN_LOCK_UNLOCKED(old_style_spin_init)" is wrong. We'll fix it.
>
> > static struct diu_hw dr = {
> > .mode = MFB_MODE1,
> > - .reg_lock = __SPIN_LOCK_UNLOCKED(old_style_spin_init),
> > + .reg_lock = __SPIN_LOCK_UNLOCKED(diu_hw.reg_lock),
> > };
>
> Yes, this is better. Did you already make this change when you applied it to
> your -mm repo?

I did:

--- a/drivers/video/fsl-diu-fb.c~fbdev-driver-for-freescale-8610-and-5121-diu-fix
+++ a/drivers/video/fsl-diu-fb.c
@@ -274,7 +274,7 @@ static struct mfb_info mfb_template[] =

static struct diu_hw dr = {
.mode = MFB_MODE1,
- .reg_lock = __SPIN_LOCK_UNLOCKED(old_style_spin_init),
+ .reg_lock = __SPIN_LOCK_UNLOCKED(dr.reg_lock),
};

static struct diu_pool pool;
> > GFP_DMA implies GFP_ATOMIC, but it's appropriate for documentation purposes.
>
> So does that mean that "GFP_DMA | GFP_KERNEL" is always wrong?

No, that's OK too. It's just that GFP_DMA|GFP_ATOMIC is a bit redundant
and misleading. GFP_DMA is already atomic; the only effect of adding
GFP_ATOMIC to GFP_DMA is to add __GFP_HIGH.
Don't wory about it ;)

> If so, this
> combination is used a lot in the kernel today.
>
> >> + if (virt) {
> >> + *phys = virt_to_phys(virt);
> >> + pr_debug("virt %p, phys=%llx\n", virt, (uint64_t) *phys);
> >> + memset(virt, 0, size);
> >
> > Could have used __GFP_ZERO, I guess.
>
> I had completely forgotten about __GFP_ZERO. Thanks.
>
> >> + virt = (void *) rh_alloc(&diu_ops.diu_rh_info, size, "DIU");
> >
> > hm, I'd have expected checkpatch to whine about the space after the cast
> > there. Whatever.
>
> I thought a space after a cast is the right thing to do?

Last time I grepped, no-space is a lot more common.

> > please take a look, and please use checkpatch on all future patches.
>
> Sorry, we forgot to run it again after our second version of the patch.
>
> >> +static void free_irq_local(int irq)
> >> +{
> >> + struct diu *hw = dr.diu_reg;
> >> +
> >> + /* Disable all LCDC interrupt */
> >> + out_be32(&(hw->int_mask), 0x1f);
> >> +
> >> + free_irq(irq, 0);
> >> +}
> >
> > and the free_irq() will go splat?
>
> Sorry, but I don't understand what's wrong with this code.

You snipped a bit. Earlier, request_irq() failures were ignored. So I
think there's a code path where free_irq_local() can free an IRQ which this
driver never owned.

> We'll make the other changes you've suggested and repost.



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