Re: [PATCH v2 0/9] brcmfmac: add support for BCM4359 SDIO chipset

[Christian Hewitt]

> On 24 Dec 2019, at 1:01 pm, Arend Van Spriel <arend.vanspriel@xxxxxxxxxxxx> wrote:
> 
> Can you elaborate on the "known SDIO issue"? Is it an issue with ADMA or something else. I am asking because there is a workaround in brcmfmac to avoid scatter-gather lists, which may or may not address the issue.

This describes the issue: https://patchwork.kernel.org/cover/10962975/

Below is the current workaround Iâm using, which restricts the hack to Amlogic G12A and G12B devices that inherit âamlogic,dram-access-quirkâ from a common SoC dtsi.

https://github.com/chewitt/linux/commit/187527747861b047c835f494fe3267d9b4959be1

Testing by Khadas staff found the max_segs/max_blk_count values and shows a performance impact (not a big surprise) but they appear to give a stable connection, which is better than a very unstable one. Iâve flagged things to linux-amlogic maintainer Neil Armstrong (on CC) and I expect he or colleagues will take a more scientific look in January.

NB: Iâm happy to test other things. Just remember that I donât code so you need to spoon-feed me with patches not suggestions.

Christian