On Sun, Dec 26, 2021 at 03:13:21PM +0200, Andy Shevchenko wrote:
On Sun, Dec 26, 2021 at 1:45 PM Gabriel L. Somlo [off-list ref] wrote:
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On Sat, Dec 25, 2021 at 06:43:22PM +0200, Andy Shevchenko wrote:
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On Wed, Dec 15, 2021 at 10:00 PM Gabriel Somlo [off-list ref] wrote:
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This is wrong. It missed the deferred probe, for example.
The best approach is
ret = platform_get_irq_optional(...);
if (ret < 0 && ret != -ENXIO)
return ret;
if (ret > 0)
...we got it...
It will allow the future API fix of platform_get_irq_optional() to be
really optional.
Thanks for the example. I still need to work in a decision to use
polling, though. How about something like this instead:
ret = platform_get_irq_optional(...);
if (ret == -ENXIO)
goto use_polling;
if (ret < 0)
return ret; // deferred probe (-EAGAIN likely?)
if (ret > 0)
...we got it, keep going...
This doesn't define what you should do when you get 0.
I suggest to take my variant with below modification
if (ret > 0)
...we have IRQ...
else
goto USE POLLING;
It will take care of the case.
OK, will do.
...
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+#ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
Why under ifdeffery?
Because I only want to do it on 64-bit capable architectures.
The alternative would be to call
dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(64));
on *all* architectures, but ignore the returned error (-EIO,
presumably on architetures that only support 32-bit DMA).
I don't understand why you are supposed to ignore errors and why you
expect to get such.
If I call `dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(64));`
on a machine where `CONFIG_ARCH_DMA_ADDR_T_64BIT` is *not* set, I
expect an error. The implicit default
(per Documentation/core-api/dma-api-howto.rst), is DMA_BIT_MASK(32).
I'm working under the impression that on machines with
CONFIG_ARCH_DMA_ADDR_T_64BIT I should increase that to DMA_BIT_MASK(64).
So if I don't #ifdef it, that call will fail on machines supporting
only 32-bits.
What am I missing?
Thanks,
--Gabriel
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Do you think that would be cleaner?
--
With Best Regards,
Andy Shevchenko