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charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-DetectorID-Processed: b00c1d49-9d2e-4205-b15f-d015386d3d5e On 7/13/26 13:23, Marc Zyngier wrote: > On Mon, 13 Jul 2026 17:15:35 +0100, > Florian Fainelli wrote: >> >> On 7/10/26 01:09, Marc Zyngier wrote: >>> It appears that the bcm2712 SoC found in the relatively popular >>> RPi5 has a broken EL2 virtual timer. >>> >>> We do not know the reason why the timer isn't working (the timer >>> is ticking, but the interrupt never fires), and the SoC vendor >>> doesn't communicate on the reason why this isn't working, leaving >>> users and maintainers in the dark. >>> >>> Paper over the issue by detecting the broken HW, falling back to >>> the physical timer instead, and let the user know about it. >>> Also taint the kernel as the machine is definitely not compliant >>> with the spec, and we don't know what else is wrong with it. >>> >>> Reported-by: John >>> Reported-by: Daniel Drake >>> Reported-by: Marek Szyprowski >>> Signed-off-by: Marc Zyngier >>> Cc: Florian Fainelli >>> Cc: Daniel Lezcano >>> Cc: Thomas Gleixner >>> Cc: Mark Rutland >> >> Acked-by: Florian Fainelli >> >> We know why now: the virtual interrupt timer line was never connected >> in the first place because it was not clarified that it was a >> requirement. > > Dangling wires coming out of the CPUs don't ring any alarm bell at > integration time? Amazing. Makes you wonder what else they forgot to > connect... > > Is there an erratum number that we can refer to for documentation > purposes? There is not one, we only have an internal bug tracker entry for this issue. -- Florian