This is now clarified in an ACPI spec ECR (https://bugzilla.tianocore.org/show_bug.cgi?id=3335). The example will be updated in a future spec errata to use ResourceProducer. I think this patch can resume as it is not gated by the spec anymore. From: Andrei Warkentin Sent: Thursday, April 8, 2021 10:25 AM To: Jeremy Linton ; devel@edk2.groups.io Cc: Ard Biesheuvel ; leif@nuviainc.com; pete@akeo.ie; Samer El-Haj-Mahmoud Subject: Re: [PATCH 0/3] SD+USB perf/DMA fixes I think Linux's behavior needs to be reconciled with the ACPI spec, which uses _DMA with ResourceConsumer, not ResourceProducer. A ________________________________ From: Jeremy Linton > Sent: Thursday, April 8, 2021 12:58 AM To: devel@edk2.groups.io > Cc: ard.biesheuvel@arm.com >; leif@nuviainc.com >; pete@akeo.ie >; samer.el-haj-mahmoud@arm.com >; Andrei Warkentin >; Jeremy Linton > Subject: [PATCH 0/3] SD+USB perf/DMA fixes A large part of why the emmc & dwc2 usb controllers haven't been working properly is because the "bus" _DMA was incorrectly tagged as a consumer, when it needs to be a producer. That is why linux has been dropping the translation value portions of _DMA(). Since the emmc2 dma (with the old B0 SoC), and the dwc2 is expected to work, lets add matching 30 bit IORT entries for them. Finally, in the shuffle the high speed cap bit override was dropped from the linux patches, and I failed to add it back to the firmware values, this caused the wifi perf to be lower than it should have been. Jeremy Linton (3): Platform/RaspberryPi/Acpitables: Enable Arasan hispeed mode Platform/RaspberryPi/AcpiTables: Add further named components Platform/RaspberryPi/AcpiTables: Correct _DMA consumer Platform/RaspberryPi/AcpiTables/Dsdt.asl | 2 +- Platform/RaspberryPi/AcpiTables/Emmc.asl | 2 +- Platform/RaspberryPi/AcpiTables/Iort.aslc | 44 ++++++++++++++++++++++++++++++- Platform/RaspberryPi/AcpiTables/Sdhc.asl | 2 +- 4 files changed, 46 insertions(+), 4 deletions(-) -- 2.13.7 IMPORTANT NOTICE: The contents of this email and any attachments are confidential and may also be privileged. If you are not the intended recipient, please notify the sender immediately and do not disclose the contents to any other person, use it for any purpose, or store or copy the information in any medium. Thank you.