Messages in this thread | | | Date | Thu, 12 Aug 2021 16:26:41 +0100 | From | Marc Zyngier <> | Subject | Re: [PATCH net-next] stmmac: align RX buffers |
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On Thu, 12 Aug 2021 15:29:06 +0100, Thierry Reding <thierry.reding@gmail.com> wrote: > > On Wed, Aug 11, 2021 at 02:23:10PM +0100, Marc Zyngier wrote:
[...]
> > I love this machine... Did this issue occur with the Denver CPUs > > disabled? > > Interestingly I've been doing some work on a newer device called Jetson > TX2 NX (which is kind of a trimmed-down version of Jetson TX2, in the > spirit of the Jetson Nano) and I can't seem to reproduce these failures > there (tested on next-20210812). > > I'll go dig out my Jetson TX2 to run the same tests there, because I've > also been using a development version of the bootloader stack and > flashing tools and all that, so it's possible that something was fixed > at that level. I don't think I've ever tried disabling the Denver CPUs, > but then I've also never seen these issues myself. > > Just out of curiosity, what version of the BSP have you been using to > flash?
I've only used the BSP for a few weeks when I got the board last year. The only thing I use from it is u-boot to chainload an upstream u-boot, and boot Debian from there.
> One other thing that I ran into: there's a known issue with the PHY > configuration. We mark the PHY on most devices as "rgmii-id" on most > devices and then the Marvell PHY driver needs to be enabled. Jetson TX2 > has phy-mode = "rgmii", so it /should/ work okay. > > Typically what we're seeing with that misconfiguration is that the > device fails to get an IP address, but it might still be worth trying to > switch Jetson TX2 to rgmii-id and using the Marvell PHY, to see if that > improves anything.
I never failed to get an IP address. Overall, networking has been solid on this machine until this patch. I'll try and mess with this when I get time, but that's probably going to be next week now.
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> > That'd be pretty annoying. Do you know if the Ethernet is a coherent > > device on this machine? or does it need active cache maintenance? > > I don't think Ethernet is a coherent device on Tegra186. I think > Tegra194 had various improvements with regard to coherency, but most > devices on Tegra186 do need active cache maintenance. > > Let me dig through some old patches and mailing list threads. I vaguely > recall prototyping a patch that did something special for outer cache > flushing, but that may have been Tegra132, not Tegra186. I also don't > think we ended up merging that because it turned out to not be needed.
ARMv8 forbid any sort of *visible* outer cache, so I really hope this is not required. We wouldn't be able to support it.
Thanks,
M.
-- Without deviation from the norm, progress is not possible.
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