Re: [PATCH 1/2 v2] Driver for Freescale 8610 and 5121 DIU

On Fri, 21 Mar 2008 11:12:30 -0500 Timur Tabi [off-list ref] wrote:

Andrew Morton wrote:

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+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.

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 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;

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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.

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+	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.

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+	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.

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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.

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+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.