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From: Matthew Garrett <matthew.garrett@nebula.com>
To: Darren Hart <dvhart@linux.intel.com>
Cc: Olof Johansson <olof@lixom.net>,
	"David S. Miller" <davem@davemloft.net>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	"H. Peter Anvin" <hpa@zytor.com>,
	"peter.p.waskiewicz.jr@intel.com"
	<peter.p.waskiewicz.jr@intel.com>,
	"andriy.shevchenko@linux.intel.com"
	<andriy.shevchenko@linux.intel.com>,
	"danders@circuitco.com" <danders@circuitco.com>,
	"vishal.l.verma@intel.com" <vishal.l.verma@intel.com>,
	Grant Likely <grant.likely@linaro.org>,
	Linus Walleij <linus.walleij@linaro.org>,
	Richard Purdie <richard.purdie@linuxfoundation.org>,
	"platform-driver-x86@vger.kernel.org"
	<platform-driver-x86@vger.kernel.org>
Subject: Re: [PATCH 4/8] minnowboard: Add base platform driver for the MinnowBoard
Date: Wed, 26 Jun 2013 04:52:46 +0000	[thread overview]
Message-ID: <1372222365.9179.4.camel@x230> (raw)
In-Reply-To: <1372221808.8177.52.camel@envy.home>

On Tue, 2013-06-25 at 21:43 -0700, Darren Hart wrote:

> 1) I need time, possibly a couple of months, to get proper ACPI support
> for these drivers into the firmware. Then I can rewrite these as ACPI
> drivers as is proper for an x86 board. I've already started down this
> path.

A couple of months pushes you back one kernel release. It's not a huge
deal. I think I side with Olof here - the kernel developers have pushed
back against hardcoded and NIHed ARM device descriptors, and given that
we have a perfectly reasonable standard in the X86 world (ie, ACPI), I'm
not enthusiastic about merging something that's (a) going to be
superseded in the near future and (b) may end up serving as an example
to others who think this is ok.

Do these boards currently boot any other OSes?

> See what happens when core kernel people are allowed to write driver
> code? How does this relate to converting this over to an ACPI device
> driver? I guess I would replace the above with
> MODULE_DEVICE_TABLE(acpi, ...) ? If I do the above.... is this still an
> evil board-file? What makes the acpi method of discover superior to
> setting up linux-hotplug via dmi?

MODULE_DEVICE_TABLE is invisible to the running driver, it just exports
metadata that udev will use to decide whether to load the driver. If a
driver is intended to deal with a specific board, DMI makes sense. If
it's intended to deal with a specific ACPI device (ie, something with a
_HID that defines the programming model), ACPI makes sense.

-- 
Matthew Garrett | mjg59@srcf.ucam.org

WARNING: multiple messages have this Message-ID (diff)
From: Matthew Garrett <matthew.garrett@nebula.com>
To: Darren Hart <dvhart@linux.intel.com>
Cc: Olof Johansson <olof@lixom.net>,
	"David S. Miller" <davem@davemloft.net>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	"H. Peter Anvin" <hpa@zytor.com>,
	"peter.p.waskiewicz.jr@intel.com"
	<peter.p.waskiewicz.jr@intel.com>,
	"andriy.shevchenko@linux.intel.com" 
	<andriy.shevchenko@linux.intel.com>,
	"danders@circuitco.com" <danders@circuitco.com>,
	"vishal.l.verma@intel.com" <vishal.l.verma@intel.com>,
	Grant Likely <grant.likely@linaro.org>,
	"Linus Walleij" <linus.walleij@linaro.org>,
	Richard Purdie <richard.purdie@linuxfoundation.org>,
	"platform-driver-x86@vger.kernel.org" 
	<platform-driver-x86@vger.kernel.org>
Subject: Re: [PATCH 4/8] minnowboard: Add base platform driver for the MinnowBoard
Date: Wed, 26 Jun 2013 04:52:46 +0000	[thread overview]
Message-ID: <1372222365.9179.4.camel@x230> (raw)
In-Reply-To: <1372221808.8177.52.camel@envy.home>

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #1: Type: text/plain; charset="utf-8", Size: 1706 bytes --]

On Tue, 2013-06-25 at 21:43 -0700, Darren Hart wrote:

> 1) I need time, possibly a couple of months, to get proper ACPI support
> for these drivers into the firmware. Then I can rewrite these as ACPI
> drivers as is proper for an x86 board. I've already started down this
> path.

A couple of months pushes you back one kernel release. It's not a huge
deal. I think I side with Olof here - the kernel developers have pushed
back against hardcoded and NIHed ARM device descriptors, and given that
we have a perfectly reasonable standard in the X86 world (ie, ACPI), I'm
not enthusiastic about merging something that's (a) going to be
superseded in the near future and (b) may end up serving as an example
to others who think this is ok.

Do these boards currently boot any other OSes?

> See what happens when core kernel people are allowed to write driver
> code? How does this relate to converting this over to an ACPI device
> driver? I guess I would replace the above with
> MODULE_DEVICE_TABLE(acpi, ...) ? If I do the above.... is this still an
> evil board-file? What makes the acpi method of discover superior to
> setting up linux-hotplug via dmi?

MODULE_DEVICE_TABLE is invisible to the running driver, it just exports
metadata that udev will use to decide whether to load the driver. If a
driver is intended to deal with a specific board, DMI makes sense. If
it's intended to deal with a specific ACPI device (ie, something with a
_HID that defines the programming model), ACPI makes sense.

-- 
Matthew Garrett | mjg59@srcf.ucam.org
ÿôèº{.nÇ+‰·Ÿ®‰­†+%ŠËÿ±éݶ\x17¥Šwÿº{.nÇ+‰·¥Š{±þG«éÿŠ{ayº\x1dʇڙë,j\a­¢f£¢·hšïêÿ‘êçz_è®\x03(­éšŽŠÝ¢j"ú\x1a¶^[m§ÿÿ¾\a«þG«éÿ¢¸?™¨è­Ú&£ø§~á¶iO•æ¬z·švØ^\x14\x04\x1a¶^[m§ÿÿÃ\fÿ¶ìÿ¢¸?–I¥

  reply	other threads:[~2013-06-26  4:52 UTC|newest]

Thread overview: 58+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-06-26  1:53 [PATCH 0/8] MinnowBoard support Darren Hart
2013-06-26  1:53 ` [PATCH 1/8] pch_gbe: Use PCH_GBE_PHY_REGS_LEN instead of 32 Darren Hart
2013-06-26  1:53 ` [PATCH 2/8] pch_uart: Add uart_clk selection for the MinnowBoard Darren Hart
2013-06-26  2:31   ` Greg Kroah-Hartman
2013-06-26  3:16     ` Darren Hart
2013-06-26  3:39       ` Greg Kroah-Hartman
2013-06-26  3:58         ` Darren Hart
2013-06-26  4:16           ` Greg Kroah-Hartman
2013-06-26  6:43           ` Jiri Slaby
2013-06-26  7:19             ` Darren Hart
2013-06-26  7:25               ` Jiri Slaby
2013-06-26 16:23                 ` Darren Hart
2013-06-26  1:53 ` [PATCH 3/8] gpio-sch: Add sch_gpio_resume_set_enable() Darren Hart
2013-06-26 21:24   ` Darren Hart
2013-06-26  1:53 ` [PATCH 4/8] minnowboard: Add base platform driver for the MinnowBoard Darren Hart
2013-06-26  4:00   ` Olof Johansson
2013-06-26  4:43     ` Darren Hart
2013-06-26  4:52       ` Matthew Garrett [this message]
2013-06-26  4:52         ` Matthew Garrett
2013-06-26  5:32         ` Darren Hart
2013-06-26  5:36           ` Matthew Garrett
2013-06-26  5:36             ` Matthew Garrett
2013-06-26  7:17             ` Darren Hart
2013-06-27  9:14   ` Linus Walleij
2013-06-28  5:43     ` Darren Hart
2013-07-04 16:26       ` Mark Brown
2013-07-20 17:37         ` Linus Walleij
2013-07-21 23:41           ` Mark Brown
2013-10-30 14:18             ` Darren Hart
2013-10-30 21:36               ` Mark Brown
2013-07-22  0:09         ` Grant Likely
2013-07-22  3:27           ` Darren Hart
2013-06-26  1:53 ` [PATCH 5/8] minnowboard-gpio: Export MinnowBoard expansion GPIO Darren Hart
2013-06-26  7:55   ` Andy Shevchenko
2013-06-26 16:21     ` Darren Hart
2013-06-27  8:18       ` Andy Shevchenko
2013-06-28  4:27         ` Darren Hart
2013-06-26  1:53 ` [PATCH 6/8] minnowboard-keys: Bind MinnowBoard buttons to arrow keys Darren Hart
2013-06-26  8:46   ` Andy Shevchenko
2013-06-26 16:28     ` Darren Hart
2013-06-26 17:16       ` Greg Kroah-Hartman
2013-06-26 17:23         ` Darren Hart
2013-06-26 19:57           ` Linus Walleij
2013-06-26 21:23             ` Darren Hart
2013-06-26  1:53 ` [PATCH 7/8] pci: Add CircuitCo VENDOR ID and MinnowBoard DEVICE ID Darren Hart
2013-06-26 16:32   ` Bjorn Helgaas
2013-06-26 17:15     ` Darren Hart
2013-06-26 19:37       ` Bjorn Helgaas
2013-06-26 21:16         ` Darren Hart
2013-06-26 21:30           ` Bjorn Helgaas
2013-06-26 21:30         ` H. Peter Anvin
2013-06-26 21:46           ` Bjorn Helgaas
2013-06-26 21:49             ` H. Peter Anvin
2013-06-26  1:53 ` [PATCH 8/8] pch_gbe: Add MinnowBoard support Darren Hart
2013-06-26  2:35   ` Bjorn Helgaas
2013-06-26  3:11     ` Darren Hart
2013-06-26  3:25     ` H. Peter Anvin
2013-06-28  5:37   ` Darren Hart

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