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Date: Thu, 2 May 2024 15:02:33 +0530
From: Sunil V L <sunilvl@ventanamicro.com>
To: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Bjorn Helgaas <helgaas@kernel.org>,
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	"Rafael J . Wysocki" <rafael@kernel.org>,
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	Haibo1 Xu <haibo1.xu@intel.com>,
	=?utf-8?B?QmrDtnJuIFTDtnBlbA==?= <bjorn@kernel.org>
Subject: Re: [PATCH v5 08/17] ACPI: pci_link: Clear the dependencies after
 probe
Message-ID: <ZjNdsWP46su9drAK@sunil-laptop>
References: <20240501121742.1215792-9-sunilvl@ventanamicro.com>
 <20240501165615.GA758227@bhelgaas>
 <ZjNcDyLRm9c7BAi3@smile.fi.intel.com>
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In-Reply-To: <ZjNcDyLRm9c7BAi3@smile.fi.intel.com>

On Thu, May 02, 2024 at 12:25:35PM +0300, Andy Shevchenko wrote:
> On Wed, May 01, 2024 at 11:56:15AM -0500, Bjorn Helgaas wrote:
> > On Wed, May 01, 2024 at 05:47:33PM +0530, Sunil V L wrote:
> > > RISC-V platforms need to use dependencies between PCI host bridge, Link
> > > devices and the interrupt controllers to ensure probe order. The
> > > dependency is like below.
> > > 
> > > Interrupt controller <-- Link Device <-- PCI Host bridge.
> > > 
> > > If there is no dependency added between Link device and PCI Host Bridge,
> > > then the PCI end points can get probed prior to link device, unable to
> > > get mapping for INTx.
> > > 
> > > So, add the link device's HID to dependency honor list and also clear it
> > > after its probe.
> > > 
> > > Since this is required only for architectures like RISC-V, enable this
> > > code under a new config option and set this only in RISC-V.
> 
> ...
> 
> > > +	if (IS_ENABLED(CONFIG_ARCH_ACPI_DEFERRED_GSI))
> > > +		acpi_dev_clear_dependencies(device);
> > 
> > This is really a question for Rafael, but it doesn't seem right that
> > this completely depends on a config option.
> 
> +1 here, fells like a hack and looks like a hack.
> 
I can remove the config option. I just thought this would probably never
required to be called on other architectures.

Unless there is an objection, I will remove it in next version.

Thanks!
Sunil
> > Is there a reason this wouldn't work for all architectures, i.e., what
> > would happen if you just called acpi_dev_clear_dependencies()
> > unconditionally?
> 
> -- 
> With Best Regards,
> Andy Shevchenko
> 
>