Date: Mon, 09 Feb 2015 16:31:32 -0500 From: John Baldwin <jhb@freebsd.org> To: Hans Petter Selasky <hps@selasky.org> Cc: usb@freebsd.org Subject: Re: r276717 causes problems Message-ID: <4020134.66atlK9cJ0@ralph.baldwin.cx> In-Reply-To: <54D92612.6000207@selasky.org> References: <20150209183648.7825eee5@ernst.home> <54D92612.6000207@selasky.org>
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On Monday, February 09, 2015 10:26:42 PM Hans Petter Selasky wrote: > Hi John, > > Do all PCI busses support 64-bit DMA busmaster? Do we reflect this in > the busdma tags passed down to device drivers? Yes, barring weird quirks. Even pre-PCI-e had a way to support 64-bit addresses for cards on a 32-bit bus using dual address cycles. Gary, do you only have problems with xhci and not other PCI devices in your system? > --HPS > > On 02/09/15 18:36, Gary Jennejohn wrote: > > r276717 breaks access to my 4-disk external USB3 (XHCI) enclosure. > > > > The symptom is that only the first of the threee disks is found. > > > > r276716 sees all the disks immediately. > > > > This is the output for the bridge chip: > > > > umass0: <JMicron USB to ATAATAPI Bridge, class 0/0, rev 3.00/28.03, addr > > 2> on usbus0 > > > > The problem seems to be mainly due to setting dma_bits to 64. It's > > true that the chip on the controller board supports 64 bit DMA, but the > > JMicron seems to have a real crisis when that setting is used, although > > I don't know why. > > > > Note that the nice output above was obtained after hard coding dma_bits > > to 32 in xhci_init(). With 64 bits I see this: > > > > umass0: <vendor 0x152d product 0x0539, class 0/0, rev 3.00/28.03, addr 3> > > on usbus0 > > > > probably because reading the strings from the device fails. > > > > Anyway, it would be nice to have a sysctl to force dma_bits to 32. > > > > Unfortunately, I still have a problem with my enclosure with more > > current versions of HEAD. The rather questionable practice of > > always doing a multi LUN enquiry using the SCSI-3 CDB byte 0xa0 > > also causes problems. Considering that most of these bridge > > chips can barely emulate SCSI-2 it seems rather foolish to try to > > jam SCSI-3 CDB bytes down their throats. > > > > But that's a different story. -- John Baldwin
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