linux-kernel - Re: [PATCH V7 5/7] ACPI: Delay the enumeration on the devices whose dependency has not met

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Message-ID: <4600523.rWNiWKrYZC@aspire.rjw.lan>
Date:   Mon, 13 Mar 2017 22:24:34 +0100
From:   "Rafael J. Wysocki" <rjw@...ysocki.net>
To:     "zhichang.yuan" <yuanzhichang@...ilicon.com>
Cc:     catalin.marinas@....com, will.deacon@....com, robh+dt@...nel.org,
        frowand.list@...il.com, bhelgaas@...gle.com, rafael@...nel.org,
        mark.rutland@....com, arnd@...db.de,
        linux-arm-kernel@...ts.infradead.org, linux-acpi@...r.kernel.org,
        lorenzo.pieralisi@....com, benh@...nel.crashing.org,
        linux-kernel@...r.kernel.org, linuxarm@...wei.com,
        devicetree@...r.kernel.org, linux-pci@...r.kernel.org,
        linux-serial@...r.kernel.org, minyard@....org, liviu.dudau@....com,
        zourongrong@...il.com, john.garry@...wei.com,
        gabriele.paoloni@...wei.com, zhichang.yuan02@...il.com,
        kantyzc@....com, xuwei5@...ilicon.com
Subject: Re: [PATCH V7 5/7] ACPI: Delay the enumeration on the devices whose  dependency has not met

On Monday, March 13, 2017 10:42:41 AM zhichang.yuan wrote:
> In commit 40e7fcb1929(ACPI: Add _DEP support to fix battery issue on Asus
> T100TA), the '_DEP' was supported to solve the dependency of Asus battery. But
> this patch is specific to Asus battery device.
> In the real world, there are other devices which need the dependency to play the
> role on the enumeration order. For example, all the Hip06 LPC
> periperals(IPMI-BT, uart, etc) must be scanned after the LPC host driver
> finished the probing. So, it makes sense to add a checking whether the ACPI
> device meet all the dependencies during its enumeration slot, if not, the
> enumeration will be delayed till all dependency master finish their work.
> 
> This patch adds the dependency checking in ACPI enumeration, also the
> corresponding handling to retrigger the Hip06 LPC peripherals' scanning.

AFAICS, _DEP is generally abused in the wild and cannot be made generic.  Sorry.

Thanks,
Rafael