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From: Andrew Jones <ajones@ventanamicro.com>
To: Conor Dooley <conor@kernel.org>
Cc: linux-riscv@lists.infradead.org, paul.walmsley@sifive.com,
	 palmer@dabbelt.com, aou@eecs.berkeley.edu,
	leyfoon.tan@starfivetech.com,  jeeheng.sia@starfivetech.com,
	conor.dooley@microchip.com, apatel@ventanamicro.com
Subject: Re: [PATCH v1 1/1] riscv: sbi: Introduce system suspend support
Date: Thu, 12 Oct 2023 15:36:31 +0200	[thread overview]
Message-ID: <20231012-391361fca6fa17b44fefd033@orel> (raw)
In-Reply-To: <20231012-powdery-demeanor-4d8dde576f24@spud>

On Thu, Oct 12, 2023 at 02:30:02PM +0100, Conor Dooley wrote:
> Yo,
> 
> On Thu, Oct 12, 2023 at 09:21:50AM +0200, Andrew Jones wrote:
> > When the SUSP SBI extension is present it implies that the standard
> > "suspend to RAM" type is available. Wire it up to the generic
> > platform suspend support, also applying the already present support
> > for non-retentive CPU suspend. When the kernel is built with
> > CONFIG_SUSPEND, one can do 'echo mem > /sys/power/state' to suspend.
> > Resumption will occur when a platform-specific wake-up event arrives.
> > 
> > Signed-off-by: Andrew Jones <ajones@ventanamicro.com>
> 
> > +static int __init sbi_system_suspend_init(void)
> > +{
> > +	if (!sbi_spec_is_0_1() && sbi_probe_extension(SBI_EXT_SUSP) > 0) {
> 
> Random thought I had reading this, was that it'll be possible to have a
> firmware that implements SBI < 2.0 that provides the SUSP extension.
> FWIW, I don't think that that is problematic, but maybe I am missing
> something that would make it so.

Right, it shouldn't matter for SUSP. In fact, I sort of wish SBI was
extension probing only (no version checks), but Anup tells me that PMU
requires also checking the version to know which functions are available.

Thanks,
drew

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  parent reply	other threads:[~2023-10-12 13:36 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-10-12  7:21 [PATCH v1 0/1] riscv: Introduce system suspend support Andrew Jones
2023-10-12  7:21 ` [PATCH v1 1/1] riscv: sbi: " Andrew Jones
2023-10-12 13:30   ` Conor Dooley
2023-10-12 13:32     ` Conor Dooley
2023-10-12 16:01       ` Andrew Jones
2023-10-12 16:39         ` Anup Patel
2023-10-12 17:25           ` Andrew Jones
2023-10-19  8:36             ` Andrew Jones
2023-10-19  9:15               ` Conor Dooley
2023-10-12 13:36     ` Andrew Jones [this message]
2023-10-13  3:48   ` Samuel Holland
2023-11-27 10:52 ` [PATCH v1 0/1] riscv: " Conor Dooley
2023-11-27 12:07   ` Andrew Jones

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