Re: [PATCH] net: stmmac: dwmac-qcom-ethqos: Configure host DMA width

[Andrew Lunn]

On Wed, May 29, 2024 at 03:50:28PM -0500, Andrew Halaney wrote:
> $Subject should be have [PATCH net] since this targets the net tree:
> 
> https://docs.kernel.org/process/maintainer-netdev.html
> 
> On Wed, May 29, 2024 at 11:39:04AM GMT, Sagar Cheluvegowda wrote:
> > Fixes: 070246e4674b ("net: stmmac: Fix for mismatched host/device DMA address width")
> > Signed-off-by: Sagar Cheluvegowda <quic_scheluve@xxxxxxxxxxx>

> Also, I think the Fixes: here would be for adding support for this SoC
> in the driver, not what's listed? Might make more sense after you have a
> proper body though.

This is a tricky one. 

Fixes: 070246e4674b ("net: stmmac: Fix for mismatched host/device DMA
address width") is when support for different DMA address widths was
added. This fix cannot easily be back ported past that.

070246e4674b first appears in v6.3-rc4.

dwmac-qcom-ethqos.c first appears in v5.1-rc1. However, Qualcomm did
not start hacking on it until v6.7-rc6. It is unclear to me without a
deep dive when Qualcomm actually started using this driver.

We might actually be looking at this the wrong way, and should in fact
be looking at when a DT patch was added that made use of the driver,
not the driver itself. If it was not used, it cannot be broken....

	Andrew