lspci XHCI "Memory at" for RPi4 (u-boot based context): FreeBSD vs. ubuntu vs. "Memory behind bridge" addresses

Mark Millard marklmi at yahoo.com
Sat Oct 3 20:01:22 UTC 2020


[Be warned that I'm reporting differences that I do not
understand. I may end up being told "nothing of interest
in these differences".]

In the later lspci -v output diff, there is the following for
the XHCI (-: FreeBSD, +: ubuntu):

-       Memory at f8000000 (64-bit, non-prefetchable)
. . .
+       Memory at 600000000 (64-bit, non-prefetchable) [size=4K]

Odder(?) is comparison of the FreeBSD address with what is
listed by both OS's for "Memory behind bridge":

        Memory behind bridge: f8000000-f80fffff [size=1M]
. . .
-       Memory at f8000000 (64-bit, non-prefetchable)

ubuntu gets a distinct address (600000000) and FreeBSD gets
an exact match to the start of the "Memory behind bridge".
(There may be a possible 32-bit address vs. 64-bit address
distinction?)

[There are also IRQ differences (81/82 for FreeBSD; 41/42 for
ubuntu) and ubuntu lists the kernel drivers used.]

For reference:

# diff -u ~/rpi4-lspci_v-*.txt | more
--- /root/rpi4-lspci_v-fbsd.txt 2020-10-03 12:19:57.162261000 -0700
+++ /root/rpi4-lspci_v-ubuntu.txt       2020-10-03 12:21:01.448646000 -0700
@@ -1,5 +1,5 @@
-00:00.0 PCI bridge: Broadcom Inc. and subsidiaries Device 2711 (prog-if 00 [Normal decode])
-       Flags: bus master, fast devsel, latency 0, IRQ 81
+00:00.0 PCI bridge: Broadcom Inc. and subsidiaries Device 2711 (rev 10) (prog-if 00 [Normal decode])
+       Flags: bus master, fast devsel, latency 0, IRQ 41
        Bus: primary=00, secondary=01, subordinate=01, sec-latency=0
        I/O behind bridge: 00000000-00000fff [size=4K]
        Memory behind bridge: f8000000-f80fffff [size=1M]
@@ -9,13 +9,15 @@
        Capabilities: [100] Advanced Error Reporting
        Capabilities: [180] Vendor Specific Information: ID=0000 Rev=0 Len=028 <?>
        Capabilities: [240] L1 PM Substates
+       Kernel driver in use: pcieport
 
 01:00.0 USB controller: VIA Technologies, Inc. VL805 USB 3.0 Host Controller (rev 01) (prog-if 30 [XHCI])
        Subsystem: VIA Technologies, Inc. VL805 USB 3.0 Host Controller
-       Flags: bus master, fast devsel, latency 0, IRQ 82
-       Memory at f8000000 (64-bit, non-prefetchable)
+       Flags: bus master, fast devsel, latency 0, IRQ 42
+       Memory at 600000000 (64-bit, non-prefetchable) [size=4K]
        Capabilities: [80] Power Management version 3
        Capabilities: [90] MSI: Enable+ Count=1/4 Maskable- 64bit+
        Capabilities: [c4] Express Endpoint, MSI 00
        Capabilities: [100] Advanced Error Reporting
+       Kernel driver in use: xhci_hcd
 


Is this odd? Expected/reasonable?

===
Mark Millard
marklmi at yahoo.com
( dsl-only.net went
away in early 2018-Mar)



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