Re: [RFC] clk: meson: t7: Intermittent boot instability and memory corruption on VIM4

[Lucas Tanure]

On 26/08/2026 10:02, Neil Armstrong wrote:
> On 8/23/26 17:40, Lucas Tanure wrote:
> > Hi,
> >
> > While testing mainline Linux on the Khadas VIM4 (Amlogic A311D2 / T7), 
> > I am hitting intermittent system instability, storage loss, and memory 
> > corruption during boot, unless I append clk_ignore_unused to the 
> > kernel command line.
> >
> > Because the failure is intermittent, I am running 100-reboot test 
> > campaigns to bisect the remaining clocks and isolate which clocks are 
> > critical and cannot be safely disabled.
> >
> > As testing takes significant time over serial console, I wanted to 
> > check if Amlogic or the maintainers could shed light on this:
> >
> > Are there specific T7 clocks or hardware domains that must remain 
> > critical/protected even without an explicit in-kernel consumer?
> >
> > Current clocks being disabled that don't kill the board on a test run:
> >
> > [    0.380313] clk: Disabling unused clocks
> > [    0.380413] clk: Disabled unused clock: rtc_dualdiv
> > [    0.380718] clk: Disabled unused clock: rtc_duandiv_in
>
> Those could be used by low power stuff aswell, not only RTC
>
> > [    0.381377] clk: Unprepared unused clock: a73_div16
> > [    0.381972] clk: Unprepared unused clock: cpu_div16
>
> Those should probably be left enabled if they're used by the DVFS code
>
> > [    0.382605] clk: Unprepared unused clock: f50m
> > [    0.383174] clk: Unprepared unused clock: fixed_pll_dco
> > [    0.383786] clk: Unprepared unused clock: hdmi_pll_osc
> > [    0.384416] clk: Unprepared unused clock: sys1_pll_osc
> > [    0.385056] clk: Unprepared unused clock: earc_osc
> > [    0.385652] clk: Unprepared unused clock: pcie_refclk_osc
> > [    0.386323] clk: Unprepared unused clock: eth_pll_osc
> > [    0.386961] clk: Unprepared unused clock: pcie_osc
> > [    0.387548] clk: Unprepared unused clock: mclk_pll_osc
> > [    0.388187] clk: Unprepared unused clock: usb_pll1_osc
> > [    0.388826] clk: Unprepared unused clock: usb_pll0_osc
> > [    0.389465] clk: Unprepared unused clock: tcon_pll_osc
> > [    0.390105] clk: Unprepared unused clock: top_pll_osc
> > [    0.390738] clk: Unprepared unused clock: aud_pll_osc
> > [    0.391361] clk: Unprepared unused clock: ddr_pll_osc
> >
> > I am not forcing any clock to be disabled; I am forcing all clocks to 
> > stay on and letting them be disabled if unused one by one.
> >
> > Any guidance or hints on required platform clocks would be greatly 
> > appreciated.
>
> It's hard to say, this is dependent on each family, Amlogic should be 
> able to help here.
Yes, Amlogic, please help.>
> You list some clocks, but I don't understand you say that it's stable 
> only if you have clk_ignore_unused, so how did you get this clock list ?
I got this list when I add logs to the clock framework and run without 
clk_ignore_unused.
> Neil
>
> > Thanks,
> > Lucas Tanure