Date: Thu, 04 Feb 2010 21:53:39 -0800 From: Nate Lawson <nate@root.org> To: Andriy Gapon <avg@icyb.net.ua> Cc: freebsd-acpi@FreeBSD.org Subject: Re: acpi_ec_ecdt_probe => acpi_ec_identify Message-ID: <4B6BB263.4040604@root.org> In-Reply-To: <4B6B4A3C.5090308@icyb.net.ua> References: <4B6B4A3C.5090308@icyb.net.ua>
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Andriy Gapon wrote: > I would like to convert acpi_ec_ecdt_probe to device_identify method. > Rationale: > 1. It doesn't look like any device is using acpi_ec's services during identify > stage (or earlier) and acpi_ec already has a rather high priority among acpi > drivers that it would probe and attach before most of them. > 2. Making a driver 'less special' is always a good thing in general. > 3. Probing/attachment of acpi_ec at the current very early stage may even fail > because it could be dependent on things done by other, even more fundamental, > drivers that provide system resources. > 4. To expand the above: on some systems EC _REG method accesses things that only > get dynamically loaded after Processor's _PDC/_OSC is evaluated[*]. Converting > acpi_ec_ecdt_probe => acpi_ec_identify won't help here, but this would be a > first step towards a solution. > > [*] > http://www.freebsd.org/cgi/query-pr.cgi?pr=kern/142561 > Followups from Jan 15 on. I agree in concept. The ECDT-based probe method was intended to get it active as early as possible, and Linux has a quirk to create a fake ECDT to get an early EC on some systems that require it but don't have an ECDT. However, I thought jhb@'s multi-pass probe work would be a better way to support this than moving it into device_identify(). Is that code ready to use yet? -- Nate
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