Messages in this thread | | | From | Jon Nettleton <> | Date | Wed, 17 Nov 2021 14:22:52 +0100 | Subject | Re: [PATCH 2/8] bus: fsl-mc: handle DMA config deferral in ACPI case |
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On Wed, Nov 17, 2021 at 2:07 PM Laurentiu Tudor <laurentiu.tudor@nxp.com> wrote: > > > > On 11/12/2021 7:31 PM, Daniel Thompson wrote: > > On Thu, Nov 11, 2021 at 06:36:58PM +0100, Jon Nettleton wrote: > >> On Thu, Nov 11, 2021 at 6:23 PM Daniel Thompson > >> <daniel.thompson@linaro.org> wrote: > >>> > >>> Hi Laurentiu > >>> > >>> On Thu, Jul 15, 2021 at 05:07:12PM +0300, laurentiu.tudor@nxp.com wrote: > >>>> From: Laurentiu Tudor <laurentiu.tudor@nxp.com> > >>>> > >>>> ACPI DMA configure API may return a defer status code, so handle it. > >>>> On top of this, move the MC firmware resume after the DMA setup > >>>> is completed to avoid crashing due to DMA setup not being done yet or > >>>> being deferred. > >>>> > >>>> Signed-off-by: Laurentiu Tudor <laurentiu.tudor@nxp.com> > >>> > >>> I saw regressions on my Honeycomb LX2 (NXP LX2060A) when I switched to > >>> v5.15. It seems like it results in so many sMMU errors that the system > >>> cannot function correctly (it's only about a 75% chance the system will > >>> boot to GUI and even if it does boot successfully the system will hang > >>> up soon after). > >>> > >>> Bisect took me up a couple of blind alleys (mostly due to unrelated boot > >>> problems in v5.14-rc2) by eventually led me to this patch as the cause. > >>> Applying/unapplying this patch to a v5.14-rc3 tree will provoke/fix the > >>> problem and reverting it against v5.15 also resolves the problem. > >>> > >>> Is there some specific firmware version required for this patch to work > >>> correctly? > >> > >> This patch was merged as a requirement for operational on board networking. > >> This was merged as a prerequisite to landing the patches to support MDIO and > >> phy initialization in general. > > > > Interesting. > > > > I assumed the change of behaviour comes from properly handling > > -EPROBE_DEFER (which can hardly be regarded as a fault with the patch). > > > > Having said that the patch does not seem to be mandatory to get the 1G > > networking working on Honeycomb LX2 (running ACPI). By taking v5.15 and > > reverting as I shared previously, I am still able to access the network > > using the 1G port on the back of the unit (although I didn't do any > > performance tests). > > > > > >> The correct solution for the problem you are seeing is the ACPI > >> maintainers figuring out how to land the IORT RMR patchset. Until > >> that is done the only workaround is setting "arm-smmu.disable_bypass=0 > >> iommu.passthrough=1" on the kernel commandline. The latter option is > >> required since 5.15 and I haven't had time or energy to figure out > >> why. The proper solution is to just land the IORT RMR patchset and > >> let HoneyComb run with the SMMU enabled. > > > > Thanks for the update. I'll probably adopt iommu.passthrough=1 for now. > > That allows me to adopt a distro kernel when it updates to v5.15. > > The "iommu.passthrough=1" kernel arg shouldn't be needed. By chance, do > you remember what errors were you seeing? What was failing?
This wasn't needed prior to 5.15, both are needed now. I have not bothered to bisect what caused it, since we have a proper solution that just needs to be merged. Then we won't need any kernel arguments.
-Jon
> > --- > Thanks & Best Regards, Laurentiu
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