Stable inclusion request: Revert "ath10k: fix DMA related firmware crashes on multiple devices" for 4.4, 4.9, 4.14, 4.19 and 5.4

Stable inclusion request: Revert "ath10k: fix DMA related firmware crashes on multiple devices" for 4.4, 4.9, 4.14, 4.19 and 5.4

[Nick Lowe]

Hi,

Please can commit a1769bb68a850508a492e3674ab1e5e479b11254 be back
merged to the 4.4, 4.9, 4.14, 4.19 and 5.4 LTS kernels to resolve a
PCIe hang with Wave 2-generation 802.11ac QCA chips?

commit a1769bb68a850508a492e3674ab1e5e479b11254
author Zhi Chen <zhichen@codeaurora.org>
date 2020-01-14 12:35:21 +0800

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=a1769bb68a850508a492e3674ab1e5e479b11254

The issue resolved is that a value of 0 has a different meaning and
instruction depending on the specific chip. Wave 1 and Wave 2 QCA
802.11ac chips use this differently.

This meant that the original commit introduced a regression for the
Wave 2-generation 802.11ac QCA chips when seeking to resolve a
firmware crash issue affecting some Wave 1-generation 802.11ac QCA
chips.

This subsequently has only been partially reverted via this commit,
specifically for the 10_4 target only via TARGET_10_4_DMA_BURST_SIZE 1

The original commit that caused this regression from back in 2015 is
76d164f582150fd0259ec0fcbc485470bcd8033e

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=76d164f582150fd0259ec0fcbc485470bcd8033e

With thanks,

Nick

Re: Stable inclusion request: Revert "ath10k: fix DMA related firmware crashes on multiple devices" for 4.4, 4.9, 4.14, 4.19 and 5.4

[Sasha Levin]

On Fri, Aug 28, 2020 at 04:07:24PM +0100, Nick Lowe wrote:
>Hi,
>
>Please can commit a1769bb68a850508a492e3674ab1e5e479b11254 be back
>merged to the 4.4, 4.9, 4.14, 4.19 and 5.4 LTS kernels to resolve a
>PCIe hang with Wave 2-generation 802.11ac QCA chips?

I've queued it up to the kernel trees listed above, thanks!

-- 
Thanks,
Sasha