linux-kernel - Re: [PATCH] ACPI / LPSS: Add device link for CHT SD card dependency on I2C

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <2405365.q2EvmcMJGf@aspire.rjw.lan>
Date:   Mon, 04 Dec 2017 15:56:23 +0100
From:   "Rafael J. Wysocki" <rjw@...ysocki.net>
To:     Hans de Goede <hdegoede@...hat.com>,
        Adrian Hunter <adrian.hunter@...el.com>
Cc:     "Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
        Mika Westerberg <mika.westerberg@...ux.intel.com>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        linux-acpi@...r.kernel.org, linux-kernel@...r.kernel.org,
        Carlo Caione <carlo@...lessm.com>
Subject: Re: [PATCH] ACPI / LPSS: Add device link for CHT SD card dependency on I2C

On Monday, December 4, 2017 3:33:29 PM CET Hans de Goede wrote:
> Hi,
> 
> On 04-12-17 15:30, Adrian Hunter wrote:
> > On 04/12/17 15:48, Hans de Goede wrote:
> >> Hi,
> >>
> >> Wouldn't it be easier to use the ACPI _DEP tracking for this, e.g.
> > 
> > It is using _DEP, see acpi_lpss_dep()
> > 
> >> add something like this to the the probe function:
> >>
> >>      struct acpi_device = ACPI_COMPANION(device);
> >>
> >>      if (acpi_device->dep_unmet)
> >>          return -EPROBE_DEFER;
> >>
> >> No idea if this will work, but if it does work, using the deps described
> >> in the ACPI tables seems like a better solution then hardcoding this.
> > 
> > That would not work because there are other devices listed in the _DEP
> > method so dep_unmet is always true.  So we are left checking _DEP but only
> > for specific device dependencies.
> 
> Ugh, understood thank you for explaining this. Perhaps it is a good idea
> to mention in the commit message why acpi_dev->dep_unmet cannot be used
> here?

Not just in the commit message, but I'd suggest adding a comment to that effect
next to the definition of lpss_device_links[].

Thanks,
Rafael