Re: [PATCH v1] pmdomain: mediatek: Fix MT8183 hang on boot

On Wed, Jul 22, 2026 at 3:28 PM Dmitry Osipenko
<[email protected]> wrote:
>
> Depending on firmware, part of the MFG domains may be left ON at boot
> leaving only some MFG cores powered, to let the ACP to prefetch the GPU
> region when the display controller is brought up. This doesn't play well
> with an eventual delay in probing Panfrost when the display controller is
> fully set up, as that would make genpd's sync_state() to power off the
> domain while ACP tries to prefetch: this is causing an AXI stall,
> effectively freezing the AP indefinitely. In order to prevent this from

I haven't made any detailed investigation, but to me, it sounds like
there is a missing consumer somewhere.

Should the ACP/panfrost devices be a consumer of the MFG domains as
well? Or perhaps, if the ACP/panfrost should rely on the display
controller to be probed and powered-on, to be able to probe?

> happening, the sync_state() functionality must be obliterated on all of
> the MFG domains: while this guarantees a power leakage if the bootloader
> boots the kernel with MFG PDs partially powered on, this is the only way
> to ensure stable operation of the SoC during boot on devices with such
> firmware because, of course, those will never officially receive a
> firmware update.
>
> Fixes Kappa Chromebook hanging during system boot.
>
> Fixes: 0e789b491ba0 ("pmdomain: core: Leave powered-on genpds on until sync_state")
> Fixes: 13a4b7fb6260 ("pmdomain: core: Leave powered-on genpds on until late_initcall_sync")
> Signed-off-by: Dmitry Osipenko <[email protected]>

Kind regards
Uffe

> ---
>  drivers/pmdomain/mediatek/mt8183-pm-domains.h | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/pmdomain/mediatek/mt8183-pm-domains.h b/drivers/pmdomain/mediatek/mt8183-pm-domains.h
> index 3742782a2702..5e33b8628e85 100644
> --- a/drivers/pmdomain/mediatek/mt8183-pm-domains.h
> +++ b/drivers/pmdomain/mediatek/mt8183-pm-domains.h
> @@ -47,7 +47,7 @@ static const struct scpsys_domain_data scpsys_domain_data_mt8183[] = {
>                 .pwr_sta2nd_offs = 0x0184,
>                 .sram_pdn_bits = 0,
>                 .sram_pdn_ack_bits = 0,
> -               .caps = MTK_SCPD_DOMAIN_SUPPLY,
> +               .caps = MTK_SCPD_DOMAIN_SUPPLY | MTK_SCPD_KEEP_DEFAULT_OFF,
>         },
>         [MT8183_POWER_DOMAIN_MFG] = {
>                 .name = "mfg",
> @@ -57,7 +57,7 @@ static const struct scpsys_domain_data scpsys_domain_data_mt8183[] = {
>                 .pwr_sta2nd_offs = 0x0184,
>                 .sram_pdn_bits = GENMASK(8, 8),
>                 .sram_pdn_ack_bits = GENMASK(12, 12),
> -               .caps = MTK_SCPD_DOMAIN_SUPPLY,
> +               .caps = MTK_SCPD_DOMAIN_SUPPLY | MTK_SCPD_KEEP_DEFAULT_OFF,
>         },
>         [MT8183_POWER_DOMAIN_MFG_CORE0] = {
>                 .name = "mfg_core0",
> @@ -67,6 +67,7 @@ static const struct scpsys_domain_data scpsys_domain_data_mt8183[] = {
>                 .pwr_sta2nd_offs = 0x0184,
>                 .sram_pdn_bits = GENMASK(8, 8),
>                 .sram_pdn_ack_bits = GENMASK(12, 12),
> +               .caps = MTK_SCPD_KEEP_DEFAULT_OFF,
>         },
>         [MT8183_POWER_DOMAIN_MFG_CORE1] = {
>                 .name = "mfg_core1",
> @@ -76,6 +77,7 @@ static const struct scpsys_domain_data scpsys_domain_data_mt8183[] = {
>                 .pwr_sta2nd_offs = 0x0184,
>                 .sram_pdn_bits = GENMASK(8, 8),
>                 .sram_pdn_ack_bits = GENMASK(12, 12),
> +               .caps = MTK_SCPD_KEEP_DEFAULT_OFF,
>         },
>         [MT8183_POWER_DOMAIN_MFG_2D] = {
>                 .name = "mfg_2d",
> @@ -85,6 +87,7 @@ static const struct scpsys_domain_data scpsys_domain_data_mt8183[] = {
>                 .pwr_sta2nd_offs = 0x0184,
>                 .sram_pdn_bits = GENMASK(8, 8),
>                 .sram_pdn_ack_bits = GENMASK(12, 12),
> +               .caps = MTK_SCPD_KEEP_DEFAULT_OFF,
>                 .bp_cfg = {
>                         BUS_PROT_WR(INFRA,
>                                     MT8183_TOP_AXI_PROT_EN_1_MFG,
> --
> 2.54.0
>