Messages in this thread Patch in this message | | | Date | Mon, 21 Nov 2022 21:10:39 +0000 | From | Conor Dooley <> | Subject | Re: [PATCH] cpuidle: riscv-sbi: Stop using non-retentive suspend |
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On Mon, Nov 21, 2022 at 12:56:47PM -0800, Palmer Dabbelt wrote: > From: Palmer Dabbelt <palmer@rivosinc.com> > > As per [1], whether or not the core can wake up from non-retentive > suspend is a platform-specific detail. We don't have any way to encode > that, so just stop using them until we've sorted that out.
For anyone playing along at home, Anup had a proposal for encoding this information (yoinked from the GH issue below): https://lore.kernel.org/all/20220727114302.302201-1-apatel@ventanamicro.com/>
> Link: https://github.com/riscv-non-isa/riscv-sbi-doc/issues/98#issuecomment-1288564687 > Fixes: 6abf32f1d9c5 ("cpuidle: Add RISC-V SBI CPU idle driver") > Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com> > > --- > > This should allow us to revert 232ccac1bd9b ("clocksource/drivers/riscv: > Events are stopped during CPU suspend"), which fixes suspend on the D1 > but breaks timers everywhere.
FWIW the revert is at: https://lore.kernel.org/linux-riscv/20221023185444.678573-1-conor@kernel.org/
Commit message is probably a little lacking as I didn't understand the problem when I wrote it. I'll respin the revert with a tidier message tomorrow.
Acked-by: Conor Dooley <conor.dooley@microchip.com>
> --- > drivers/cpuidle/cpuidle-riscv-sbi.c | 11 +++++++++++ > 1 file changed, 11 insertions(+) > > diff --git a/drivers/cpuidle/cpuidle-riscv-sbi.c b/drivers/cpuidle/cpuidle-riscv-sbi.c > index 05fe2902df9a..9d1063a54495 100644 > --- a/drivers/cpuidle/cpuidle-riscv-sbi.c > +++ b/drivers/cpuidle/cpuidle-riscv-sbi.c > @@ -214,6 +214,17 @@ static bool sbi_suspend_state_is_valid(u32 state) > if (state > SBI_HSM_SUSPEND_NON_RET_DEFAULT && > state < SBI_HSM_SUSPEND_NON_RET_PLATFORM) > return false; > + > + /* > + * Whether or not RISC-V systems deliver interrupts to harts in a > + * non-retentive suspend state is a platform-specific detail. This can > + * leave the hart unable to wake up, so just mark these states as > + * unsupported until we have a mechanism to expose these > + * platform-specific details to Linux. > + */ > + if (state & SBI_HSM_SUSP_NON_RET_BIT) > + return false; > + > return true; > } > > -- > 2.38.1 >
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