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

[Brian Masney <bmasney@redhat.com>]

Hi Lucas,

On Wed, Aug 26, 2026 at 05:42:01PM +0100, Lucas Tanure wrote:
> With Brian's patches, VIM4 does not turn off 4 clocks:
> 
> t7_sys_sd_emmc_b
> t7_sys_sd_emmc_c
> sd_emmc_b
> sd_emmc_c
> 
> This is expected since I'm trying to run from an SD card. However, even with
> these four clocks kept enabled, the board still hangs.
> 
> Complete list with all clocks being disabled after Brians patches:
> [    1.002247] clk: Disabled unused clock: t7_sys_pwm_ao_gh
> [    1.002898] clk: Disabled unused clock: t7_sys_pwm_ao_ef
> [    1.003560] clk: Disabled unused clock: t7_sys_pwm_ao_cd
> [    1.004220] clk: Disabled unused clock: t7_sys_pwm_ao_ab
> [    1.004972] clk: Disabled unused clock: t7_sys_pwm_ef
> [    1.005509] clk: Disabled unused clock: t7_sys_pwm_cd
> [    1.006211] clk: Disabled unused clock: t7_sys_pwm_ab
> [    1.006766] clk: Disabled unused clock: t7_sys_ts_hevc
> [    1.007434] clk: Disabled unused clock: t7_sys_ts_vpu
> [    1.008033] clk: Disabled unused clock: t7_sys_ts_nna
> [    1.008741] clk: Disabled unused clock: t7_sys_ts_gpu
> [    1.009294] clk: Disabled unused clock: t7_sys_sar_adc
> [    1.009929] clk: Disabled unused clock: t7_sys_vpu_intr
> [    1.010609] clk: Disabled unused clock: t7_sys_dspb
> [    1.011186] clk: Disabled unused clock: t7_sys_dspa
> [    1.011792] clk: Disabled unused clock: t7_sys_a73pclk_apb
> [    1.012554] clk: Disabled unused clock: t7_sys_pclk_sys_apb
> [    1.013213] clk: Disabled unused clock: t7_sys_rsa
> [    1.013811] clk: Disabled unused clock: t7_sys_mipi_isp_pclk
> [    1.014529] clk: Disabled unused clock: t7_sys_mmc_apb
> [    1.015107] clk: Disabled unused clock: t7_sys_hdmirx_pclk
> [    1.015819] clk: Disabled unused clock: t7_sys_i2c_s_a
> [    1.016429] clk: Disabled unused clock: t7_sys_hdmitx_apb
> [    1.017109] clk: Disabled unused clock: t7_sys_i2c_m_f
> [    1.017740] clk: Disabled unused clock: t7_sys_i2c_m_e
> [    1.018379] clk: Disabled unused clock: t7_sys_i2c_m_d
> [    1.019018] clk: Disabled unused clock: t7_sys_i2c_m_c
> [    1.019657] clk: Disabled unused clock: t7_sys_i2c_m_b
> [    1.020296] clk: Disabled unused clock: t7_sys_i2c_m_a
> [    1.020940] clk: Disabled unused clock: t7_sys_i2c_ao_b
> [    1.021585] clk: Disabled unused clock: t7_sys_i2c_ao_a
> [    1.022236] clk: Disabled unused clock: t7_sys_pcie_phy
> [    1.022885] clk: Disabled unused clock: t7_sys_usb
> [    1.023482] clk: Disabled unused clock: t7_sys_pcie
> [    1.024088] clk: Disabled unused clock: t7_sys_spicc1
> [    1.024723] clk: Disabled unused clock: t7_sys_spicc0
> [    1.025345] clk: Disabled unused clock: t7_sys_g2d
> [    1.025940] clk: Disabled unused clock: t7_sys_spicc5
> [    1.026569] clk: Disabled unused clock: t7_sys_ts_a53
> [    1.027197] clk: Disabled unused clock: t7_sys_ts_a73
> [    1.027825] clk: Disabled unused clock: t7_sys_spicc4
> [    1.028454] clk: Disabled unused clock: t7_sys_spicc3
> [    1.029085] clk: Disabled unused clock: t7_sys_spicc2
> [    1.029710] clk: Disabled unused clock: t7_sys_aififo
> [    1.030339] clk: Disabled unused clock: t7_sys_uart_f
> [    1.030967] clk: Disabled unused clock: t7_sys_uart_e
> [    1.031595] clk: Disabled unused clock: t7_sys_uart_d
> [    1.032224] clk: Disabled unused clock: t7_sys_uart_c
> [    1.032857] clk: Disabled unused clock: t7_sys_uart_b
> [    1.033482] clk: Disabled unused clock: t7_sys_eth
> [    1.034077] clk: Disabled unused clock: t7_sys_audio
> [    1.034694] clk: Disabled unused clock: t7_sys_ir_ctrl
> [    1.035333] clk: Disabled unused clock: t7_sys_msr_clk
> [    1.035972] clk: Disabled unused clock: t7_sys_spifc
> [    1.036596] clk: Disabled unused clock: t7_sys_acodec
> [    1.037218] clk: Disabled unused clock: t7_sys_smartcard
> [    1.037880] clk: Disabled unused clock: t7_sys_am2axi2
> [    1.038518] clk: Disabled unused clock: t7_sys_am2axi1
> [    1.039157] clk: Disabled unused clock: t7_sys_am2axi0
> [    1.039796] clk: Disabled unused clock: t7_sys_ampipe_eth
> [    1.040468] clk: Disabled unused clock: t7_sys_ampipe_nand
> [    1.041155] clk: Disabled unused clock: t7_sys_deswarp
> [    1.041790] clk: Disabled unused clock: t7_sys_gdc
> [    1.042385] clk: Disabled unused clock: t7_sys_cec
> [    1.042981] clk: Disabled unused clock: t7_sys_aucpu
> [    1.043600] clk: Disabled unused clock: t7_sys_aocpu
> [    1.044217] clk: Disabled unused clock: t7_sys_mali
> [    1.044830] clk: Disabled unused clock: t7_sys_ethphy
> [    1.045451] clk: Disabled unused clock: t7_sys_mipi_dsi_b
> [    1.046123] clk: Disabled unused clock: t7_sys_mipi_dsi_a
> [    1.046795] clk: Disabled unused clock: t7_sys_dos
> [    1.047390] clk: Disabled unused clock: t7_sys_ddr
> [    1.047991] clk: Disabled unused clock: pwm_ao_g
> [    1.048565] clk: Disabled unused clock: pwm_ao_f
> [    1.049135] clk: Disabled unused clock: pwm_ao_e
> [    1.049709] clk: Disabled unused clock: pwm_ao_d
> [    1.050283] clk: Disabled unused clock: pwm_ao_b
> [    1.050857] clk: Disabled unused clock: pwm_ao_a
> [    1.051454] clk: Disabled unused clock: rtc_dualdiv
> [    1.052038] clk: Disabled unused clock: rtc_duandiv_in
> 
> Also with the patches the disable happens 0.5 second later, from 0.5 seconds
> after the boot to 1 second after the boot.
> 
> I am still investigating what is missing a consumer or what should be
> labeled critical.

I've seen cases where a clock is modeled in Linux, but isn't actually
used by Linux, so it gets caught in the disable unused clocks sweep.

Does the board immediately crash after the disable unused clock sweep?
If so, you could add a log statement, then 1 second sleep in
clk_disable_unused_subtree() and wait for the board to crash.

If you can't get timely help from the vendor, then you can add
CLK_IGNORE_UNUSED to all of those clocks, and slowly start taking them
off in batches and wait for the crash.

Brian