Date: Fri, 05 Feb 2010 08:16:15 +0200 From: Andriy Gapon <avg@icyb.net.ua> To: Nate Lawson <nate@root.org> Cc: freebsd-acpi@FreeBSD.org, John Baldwin <jhb@FreeBSD.org> Subject: Re: acpi_ec_ecdt_probe => acpi_ec_identify Message-ID: <4B6BB7AF.3040205@icyb.net.ua> In-Reply-To: <4B6BB263.4040604@root.org> References: <4B6B4A3C.5090308@icyb.net.ua> <4B6BB263.4040604@root.org>
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on 05/02/2010 07:53 Nate Lawson said the following: > 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? I agree with this. But, unfortunately, the code doesn't seem to be as ready as everyone would love it to be. -- Andriy Gapon
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