How to resolve an issue in swiotlb environment?

Greg KH gregkh at linuxfoundation.org
Thu Jun 13 18:18:17 UTC 2019


On Thu, Jun 13, 2019 at 01:16:32PM -0400, Alan Stern wrote:
> On Thu, 13 Jun 2019, Christoph Hellwig wrote:
> 
> > On Wed, Jun 12, 2019 at 10:43:11AM -0400, Alan Stern wrote:
> > > Would it be okay to rely on the assumption that USB block devices never 
> > > have block size < 512?  (We could even add code to the driver to 
> > > enforce this, although refusing to handle such devices at all might be 
> > > worse than getting an occasional error.)
> > 
> > sd.c only supports a few specific sector size, and none of them is
> > < 512 bytes:
> > 
> > 	if (sector_size != 512 &&
> > 	    sector_size != 1024 &&
> > 	    sector_size != 2048 &&
> > 	    sector_size != 4096) {
> > 	    	...
> > 		sdkp->capacity = 0;
> 
> Great!  So all we have to do is fix vhci-hcd.  Then we can remove all 
> the virt_boundary_mask stuff from usb-storage and uas entirely.
> 
> (I'm assuming wireless USB isn't a genuine issue.  As far as I know, it 
> is pretty much abandoned at this point.)

It is, I need to just move it to staging and delete the thing.  I don't
know of any hardware anymore.

thanks,

greg k-h


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