Re: [BISECTED REGRESSION] b43legacy broken on G4 PowerBook

From: Larry Finger
Date: Tue Jun 11 2019 - 22:02:11 EST

On 6/11/19 5:46 PM, Aaro Koskinen wrote:

On Tue, Jun 11, 2019 at 05:20:12PM -0500, Larry Finger wrote:
It is obvious that the case of a mask smaller than min_mask should be
handled by the IOMMU. In my system, CONFIG_IOMMU_SUPPORT is selected. All
other CONFIG variables containing IOMMU are not selected. When
dma_direct_supported() fails, should the system not try for an IOMMU
solution? Is the driver asking for the wrong type of memory? It is doing a
dma_and_set_mask_coherent() call.

I don't think we have IOMMU on G4. On G5 it should work (I remember fixing
b43 issue on G5, see 4c374af5fdee, unfortunately all my G5 Macs with b43
are dead and waiting for re-capping).

You are right. My configuration has CONFIG_IOMMU_SUPPORT=y, but there is no mention of an IOMMU in the log.