Re: [BISECTED REGRESSION] b43legacy broken on G4 PowerBook
From: Christoph Hellwig
Date: Mon Jun 10 2019 - 04:23:15 EST
On Sat, Jun 08, 2019 at 04:52:24PM -0500, Larry Finger wrote:
> On 6/7/19 12:29 PM, Christoph Hellwig wrote:
>> I don't think we should work around this in the driver, we need to fix
>> it in the core. I'm curious why my previous patch didn't work. Can
>> you throw in a few printks what failed? I.e. did dma_direct_supported
>> return false? Did the actual allocation fail?
> Routine dma_direct_supported() returns true.
> The failure is in routine dma_set_mask() in the following if test:
> if (!dev->dma_mask || !dma_supported(dev, mask))
> return -EIO;
> For b43legacy, dev->dma_mask is 0xc265684800000000.
> dma_supported(dev, mask) is 0xc08b000000000000, mask is 0x3fffffff, and
> the routine returns -EIO.
> For b43, dev->dma_mask is 0xc265684800000001,
> dma_supported(dev, mask) is 0xc08b000000000000, mask is 0x77777777, and
> the routine returns 0.
I don't fully understand what values the above map to. Can you send
me your actual debugging patch as well?