"Steinar H. Gunderson" <sgunderson@xxxxxxxxxxx> writes: > On Tue, Nov 17, 2015 at 03:16:55PM -0500, Alan Stern wrote: >> xHCI always uses 64-bit addresses. But many EHCI controllers don't, >> and only a few of the EHCI platform drivers support 64-bit DMA. > > OK, sure. But are systems with USB2 only and more than 4GB of RAM common? Hmpff. They are common in my house at least :) bjorn@nemi:~$ lspci -nn|grep USB 00:1a.0 USB controller [0c03]: Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #4 [8086:2937] (rev 03) 00:1a.1 USB controller [0c03]: Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #5 [8086:2938] (rev 03) 00:1a.2 USB controller [0c03]: Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #6 [8086:2939] (rev 03) 00:1a.7 USB controller [0c03]: Intel Corporation 82801I (ICH9 Family) USB2 EHCI Controller #2 [8086:293c] (rev 03) 00:1d.0 USB controller [0c03]: Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #1 [8086:2934] (rev 03) 00:1d.1 USB controller [0c03]: Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #2 [8086:2935] (rev 03) 00:1d.2 USB controller [0c03]: Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #3 [8086:2936] (rev 03) 00:1d.7 USB controller [0c03]: Intel Corporation 82801I (ICH9 Family) USB2 EHCI Controller #1 [8086:293a] (rev 03) bjorn@nemi:~$ grep MemTotal /proc/meminfo MemTotal: 8051536 kB bjorn@canardo:~$ lspci -nn|grep USB 00:1a.0 USB controller [0c03]: Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #4 [8086:2937] (rev 02) 00:1a.1 USB controller [0c03]: Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #5 [8086:2938] (rev 02) 00:1a.2 USB controller [0c03]: Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #6 [8086:2939] (rev 02) 00:1a.7 USB controller [0c03]: Intel Corporation 82801I (ICH9 Family) USB2 EHCI Controller #2 [8086:293c] (rev 02) 00:1d.0 USB controller [0c03]: Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #1 [8086:2934] (rev 02) 00:1d.1 USB controller [0c03]: Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #2 [8086:2935] (rev 02) 00:1d.2 USB controller [0c03]: Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #3 [8086:2936] (rev 02) 00:1d.7 USB controller [0c03]: Intel Corporation 82801I (ICH9 Family) USB2 EHCI Controller #1 [8086:293a] (rev 02) bjorn@canardo:~$ grep MemTotal /proc/meminfo MemTotal: 8195224 kB Most systems of that generation can take 8GB RAM, and there isn't really any reason not to max that out, is there? > (And will they not increasingly die out, if nothing else as USB3 becomes > commonplace?) Can you wait 10 years for that to happen, or do you want a solution earlier? Bjørn -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
