Re: port-arm/57643: aarch64: smmu(4) seems mandatory for some SoC and/or memory configuration

[Rin Okuyama <rokuyama.rk%gmail.com@localhost>]

The following reply was made to PR port-arm/57643; it has been noted by GNATS.

From: Rin Okuyama <rokuyama.rk%gmail.com@localhost>
To: port-arm-maintainer%netbsd.org@localhost, gnats-admin%netbsd.org@localhost, 
	netbsd-bugs%netbsd.org@localhost, gnats-bugs%netbsd.org@localhost
Cc: 
Subject: Re: port-arm/57643: aarch64: smmu(4) seems mandatory for some SoC
 and/or memory configuration
Date: Tue, 10 Oct 2023 13:08:31 +0900

 Some unsuccessful tries:
 
 (1) UEFI firmware crashes for another 2GB module by other vendor.
 
 (2) wm(4) driver (since rev 1.69 back to 2004) imposes a boundary
     condition for TX/RX descriptors, to forbid across 4GB boundaries:
 
 http://cvsweb.netbsd.org/bsdweb.cgi/src/sys/dev/pci/if_wm.c#rev1.69
 https://nxr.netbsd.org/xref/src/sys/dev/pci/if_wm.c#wm_alloc_tx_descs
 
     But this is irrelevant in this case; descriptor buffer is not
     across 4GB boundaries when this symptom is observed.
 
 (3) The problem cannot be reproduced for a I226 card:
 
 igc0 at pci3 dev 0 function 0: Intel(R) Ethernet Controller I226-V (rev. 0x04)
 
     But this is a dual port card, and it may be just because a
     device is internally connected via ppb(4):
 
 pci1 at acpipchb1 bus 1
 pci1: i/o space, memory space enabled, rd/line, rd/mult, wr/inv o
 ppb0 at pci1 dev 0 function 0: vendor 1b21 product 1182 (rev. 0x00)
 ppb0: PCI Express capability version 2 <Upstream Port of PCI-E Switch>
 pci2 at ppb0 bus 2
 pci2: i/o space, memory space enabled
 ppb1 at pci2 dev 3 function 0: vendor 1b21 product 1182 (rev. 0x00)
 ppb1: PCI Express capability version 2 <Downstream Port of PCI-E
 Switch> x1 @ 5.0GT/s
 pci3 at ppb1 bus 3
 
     I ordered a single port I226 card as well as a dual port I225 in
     order to confirm this scenario.
 
 Thanks,
 rin