From: Nicolas Pitre <nico@fluxnic.net> To: Russell King - ARM Linux <linux@arm.linux.org.uk> Cc: "Pali Rohár" <pali.rohar@gmail.com>, "Rob Herring" <robherring2@gmail.com>, "Pavel Machek" <pavel@ucw.cz>, "Will Deacon" <will.deacon@arm.com>, "Ivaylo Dimitrov" <ivo.g.dimitrov.75@gmail.com>, "Sebastian Reichel" <sre@debian.org>, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>, "linux-arm-kernel@lists.infradead.org" <linux-arm-kernel@lists.infradead.org>, "Tony Lindgren" <tony@atomide.com> Subject: Re: [PATCH] ARM: /proc/atags: Export also for DT Date: Tue, 27 Jan 2015 21:07:43 -0500 (EST) [thread overview] Message-ID: <alpine.LFD.2.11.1501272027390.1322@knanqh.ubzr> (raw) In-Reply-To: <20150127223331.GP26493@n2100.arm.linux.org.uk> On Tue, 27 Jan 2015, Russell King - ARM Linux wrote: > On Tue, Jan 27, 2015 at 04:34:47PM -0500, Nicolas Pitre wrote: > > On Tue, 27 Jan 2015, Russell King - ARM Linux wrote: > > > Or we pass both the ATAGs and wrapped DT to the kernel when both exist, > > > and let the kernel deal with it in a much saner environment than the > > > restricted decompressor environment. > > > > ... which would be a step backward in the context of the transition to > > DT we accepted. People will have even less of an incentive to fix their > > stuff. > > Where's the people fixing their stuff today? At least some people in this thread are, otherwise they'd still be away hacking on their own. > I think your position is something of an idealist rather than a > realist - the reality is that five years down the line of DT, the > platforms which have not converted are now *never* going to convert, > irrespective of how much "incentive" we may think we should apply to > the situation. Don't get me wrong. I'm not expecting those platforms to do native DT booting ever. However "faking" DT booting with already proven solutions that don't bastardize the kernel further should be encouraged. > > If there is indeed a sizable following for the device then someone > > should figure out how to cope with upstream kernels, either through the > > installation of some intermediate bootloader that can talk FDT directly, > > or via a shim layer. None of that has to be performed by nor linked > > with the kernel binary, nor maintained in the kernel tree. And it's not > > even that hard to do: we have precedents on other platforms with crappy > > bootloaders where this just works. > > That's a rediculous position if you want something which "just works" > on as much hardware as possible, which is, after all, what the single > zImage project is all about. Agreed. > To be pro single-zImage, and anti popular hardware is quite contradictory. Indeed. I'm not against popular hardware. > You only have to look at x86 for this: just because ACPI came along does > not mean that the Linux kernel started demanding that ACPI is the only > way to describe the world. Linux continues to directly support all the > old boot protocols that it did since the days of i386, such as the e820 > memory interface and doesn't convert these to an ACPI table just because > it can. Booting from a floppy boot sector is no longer supported though. But that's besides the point. If someone needs a 5-line addition to atags_to_fdt.c in order to boot some old stuff then let's just do it and move on. I'll happily ACK the patch. The code is there and it is not going away soon. However, if something more involved is needed, is platform specific and is likely to require about as many lines in the kernel than it would need in some externat shim then the shim solution should be encouraged instead. After all that's why LILO, Syslinux and Grub were created on X86: to Supplement the crappy PC BIOS boot interface. And if the hardware is popular, then finding a motivated hacker to do it shouldn't be too hard, right? In other words, what prevents someone from creating, say, a custom minimal Barebox version that sits on top of the existing N900 bootloader? Wouldn't that provide a much better user experience? Nicolas
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From: nico@fluxnic.net (Nicolas Pitre) To: linux-arm-kernel@lists.infradead.org Subject: [PATCH] ARM: /proc/atags: Export also for DT Date: Tue, 27 Jan 2015 21:07:43 -0500 (EST) [thread overview] Message-ID: <alpine.LFD.2.11.1501272027390.1322@knanqh.ubzr> (raw) In-Reply-To: <20150127223331.GP26493@n2100.arm.linux.org.uk> On Tue, 27 Jan 2015, Russell King - ARM Linux wrote: > On Tue, Jan 27, 2015 at 04:34:47PM -0500, Nicolas Pitre wrote: > > On Tue, 27 Jan 2015, Russell King - ARM Linux wrote: > > > Or we pass both the ATAGs and wrapped DT to the kernel when both exist, > > > and let the kernel deal with it in a much saner environment than the > > > restricted decompressor environment. > > > > ... which would be a step backward in the context of the transition to > > DT we accepted. People will have even less of an incentive to fix their > > stuff. > > Where's the people fixing their stuff today? At least some people in this thread are, otherwise they'd still be away hacking on their own. > I think your position is something of an idealist rather than a > realist - the reality is that five years down the line of DT, the > platforms which have not converted are now *never* going to convert, > irrespective of how much "incentive" we may think we should apply to > the situation. Don't get me wrong. I'm not expecting those platforms to do native DT booting ever. However "faking" DT booting with already proven solutions that don't bastardize the kernel further should be encouraged. > > If there is indeed a sizable following for the device then someone > > should figure out how to cope with upstream kernels, either through the > > installation of some intermediate bootloader that can talk FDT directly, > > or via a shim layer. None of that has to be performed by nor linked > > with the kernel binary, nor maintained in the kernel tree. And it's not > > even that hard to do: we have precedents on other platforms with crappy > > bootloaders where this just works. > > That's a rediculous position if you want something which "just works" > on as much hardware as possible, which is, after all, what the single > zImage project is all about. Agreed. > To be pro single-zImage, and anti popular hardware is quite contradictory. Indeed. I'm not against popular hardware. > You only have to look at x86 for this: just because ACPI came along does > not mean that the Linux kernel started demanding that ACPI is the only > way to describe the world. Linux continues to directly support all the > old boot protocols that it did since the days of i386, such as the e820 > memory interface and doesn't convert these to an ACPI table just because > it can. Booting from a floppy boot sector is no longer supported though. But that's besides the point. If someone needs a 5-line addition to atags_to_fdt.c in order to boot some old stuff then let's just do it and move on. I'll happily ACK the patch. The code is there and it is not going away soon. However, if something more involved is needed, is platform specific and is likely to require about as many lines in the kernel than it would need in some externat shim then the shim solution should be encouraged instead. After all that's why LILO, Syslinux and Grub were created on X86: to Supplement the crappy PC BIOS boot interface. And if the hardware is popular, then finding a motivated hacker to do it shouldn't be too hard, right? In other words, what prevents someone from creating, say, a custom minimal Barebox version that sits on top of the existing N900 bootloader? Wouldn't that provide a much better user experience? Nicolas
next prev parent reply other threads:[~2015-01-28 2:07 UTC|newest] Thread overview: 197+ messages / expand[flat|nested] mbox.gz Atom feed top 2014-06-18 16:54 [PATCH] ARM: /proc/cpuinfo: Use DT machine name when possible Pali Rohár 2014-06-18 16:54 ` Pali Rohár 2014-06-18 19:01 ` Russell King - ARM Linux 2014-06-18 19:01 ` Russell King - ARM Linux 2014-06-18 19:09 ` Pali Rohár 2014-06-18 19:09 ` Pali Rohár 2014-06-18 19:59 ` Russell King - ARM Linux 2014-06-18 19:59 ` Russell King - ARM Linux 2014-06-19 8:21 ` Pavel Machek 2014-06-19 8:21 ` Pavel Machek 2014-07-11 19:31 ` Pavel Machek 2014-07-11 19:31 ` Pavel Machek 2014-06-18 19:07 ` Rob Herring 2014-06-18 19:07 ` Rob Herring 2014-06-18 19:22 ` Pali Rohár 2014-06-18 19:22 ` Pali Rohár 2014-06-18 20:00 ` Russell King - ARM Linux 2014-06-18 20:00 ` Russell King - ARM Linux 2014-06-18 20:20 ` Pali Rohár 2014-06-18 20:20 ` Pali Rohár 2014-06-18 21:53 ` Fabio Estevam 2014-06-18 21:53 ` Fabio Estevam 2014-11-24 22:16 ` Pali Rohár 2014-11-24 22:16 ` Pali Rohár 2014-06-18 20:46 ` Rob Herring 2014-06-18 20:46 ` Rob Herring 2014-06-18 21:47 ` Russell King - ARM Linux 2014-06-18 21:47 ` Russell King - ARM Linux 2014-06-18 22:27 ` Rob Herring 2014-06-18 22:27 ` Rob Herring 2014-06-18 23:07 ` Russell King - ARM Linux 2014-06-18 23:07 ` Russell King - ARM Linux 2014-11-24 22:19 ` Pali Rohár 2014-11-24 22:19 ` Pali Rohár 2014-12-04 0:33 ` Rob Herring 2014-12-04 0:33 ` Rob Herring 2014-12-04 0:48 ` Pali Rohár 2014-12-04 0:48 ` Pali Rohár 2014-12-04 16:49 ` Rob Herring 2014-12-04 16:49 ` Rob Herring 2014-12-04 17:57 ` Pali Rohár 2014-12-04 17:57 ` Pali Rohár 2014-12-04 18:10 ` Rob Herring 2014-12-04 18:10 ` Rob Herring 2015-01-26 19:09 ` [PATCH] ARM: /proc/cpuinfo: DT: Add support for Revision Pali Rohár 2015-01-26 19:09 ` Pali Rohár 2015-01-26 20:22 ` Rob Herring 2015-01-26 20:22 ` Rob Herring 2015-01-30 14:14 ` Pali Rohár 2015-01-30 14:14 ` Pali Rohár 2015-01-30 21:03 ` Rob Herring 2015-01-30 21:03 ` Rob Herring 2015-02-27 15:45 ` Pali Rohár 2015-02-27 15:45 ` Pali Rohár 2015-02-27 15:55 ` [PATCH v2 0/2] " Pali Rohár 2015-02-27 15:55 ` Pali Rohár 2015-02-27 15:55 ` [PATCH v2 1/2] arm: devtree: Set system_rev from DT revision Pali Rohár 2015-02-27 15:55 ` Pali Rohár 2015-02-27 15:55 ` [PATCH v2 2/2] arm: boot: convert ATAG_REVISION to DT revision field Pali Rohár 2015-02-27 15:55 ` Pali Rohár 2015-03-02 11:28 ` [PATCH v2 0/2] ARM: /proc/cpuinfo: DT: Add support for Revision Pavel Machek 2015-03-02 11:28 ` Pavel Machek 2015-03-16 15:44 ` Tony Lindgren 2015-03-16 15:44 ` Tony Lindgren 2015-03-16 16:14 ` Russell King - ARM Linux 2015-03-16 16:14 ` Russell King - ARM Linux 2015-03-16 16:43 ` Nicolas Pitre 2015-03-16 16:43 ` Nicolas Pitre 2015-03-16 19:21 ` Russell King - ARM Linux 2015-03-16 19:21 ` Russell King - ARM Linux 2015-03-16 18:10 ` Tony Lindgren 2015-03-16 18:10 ` Tony Lindgren 2015-03-16 19:59 ` Russell King - ARM Linux 2015-03-16 19:59 ` Russell King - ARM Linux 2015-03-16 20:54 ` Pali Rohár 2015-03-16 20:54 ` Pali Rohár 2015-03-16 20:59 ` Tony Lindgren 2015-03-16 20:59 ` Tony Lindgren 2015-01-26 22:34 ` [PATCH] " Andreas Färber 2015-01-26 22:34 ` Andreas Färber 2015-02-27 15:56 ` Pali Rohár 2015-02-27 15:56 ` Pali Rohár 2015-01-26 19:16 ` [PATCH] ARM: /proc/atags: Export also for DT Pali Rohár 2015-01-26 19:16 ` Pali Rohár 2015-01-26 20:33 ` Rob Herring 2015-01-26 20:33 ` Rob Herring 2015-01-27 13:21 ` Pavel Machek 2015-01-27 13:21 ` Pavel Machek 2015-01-27 14:16 ` Rob Herring 2015-01-27 14:16 ` Rob Herring 2015-01-27 14:24 ` Pavel Machek 2015-01-27 14:24 ` Pavel Machek 2015-01-27 14:32 ` Pali Rohár 2015-01-27 14:32 ` Pali Rohár 2015-01-27 17:48 ` Russell King - ARM Linux 2015-01-27 17:48 ` Russell King - ARM Linux 2015-01-27 20:03 ` Nicolas Pitre 2015-01-27 20:03 ` Nicolas Pitre 2015-01-27 21:09 ` Russell King - ARM Linux 2015-01-27 21:09 ` Russell King - ARM Linux 2015-01-27 21:34 ` Nicolas Pitre 2015-01-27 21:34 ` Nicolas Pitre 2015-01-27 21:58 ` Nicolas Pitre 2015-01-27 21:58 ` Nicolas Pitre 2015-01-27 22:33 ` Russell King - ARM Linux 2015-01-27 22:33 ` Russell King - ARM Linux 2015-01-28 2:07 ` Nicolas Pitre [this message] 2015-01-28 2:07 ` Nicolas Pitre 2015-01-28 6:21 ` Jean-Christophe PLAGNIOL-VILLARD 2015-01-28 6:21 ` Jean-Christophe PLAGNIOL-VILLARD 2015-01-28 7:19 ` Pavel Machek 2015-01-28 7:19 ` Pavel Machek 2015-01-28 8:06 ` Jean-Christophe PLAGNIOL-VILLARD 2015-01-28 8:06 ` Jean-Christophe PLAGNIOL-VILLARD 2015-01-28 8:25 ` Pavel Machek 2015-01-28 8:25 ` Pavel Machek 2015-01-28 7:18 ` Pavel Machek 2015-01-28 7:18 ` Pavel Machek 2015-01-28 13:38 ` Pali Rohár 2015-01-28 13:38 ` Pali Rohár 2015-01-27 23:10 ` Pavel Machek 2015-01-27 23:10 ` Pavel Machek 2015-01-28 0:50 ` Tony Lindgren 2015-01-28 0:50 ` Tony Lindgren 2015-01-28 13:58 ` Pali Rohár 2015-01-28 13:58 ` Pali Rohár 2015-01-28 14:33 ` Nicolas Pitre 2015-01-28 15:39 ` Tony Lindgren 2015-01-28 15:39 ` Tony Lindgren 2015-01-28 15:47 ` Pali Rohár 2015-01-28 15:47 ` Pali Rohár 2015-01-28 15:48 ` Tony Lindgren 2015-01-28 15:48 ` Tony Lindgren 2015-01-28 16:31 ` Jason Cooper 2015-01-28 16:31 ` Jason Cooper 2015-01-28 15:57 ` Rob Herring 2015-01-28 15:57 ` Rob Herring 2015-01-28 16:13 ` Russell King - ARM Linux 2015-01-28 16:13 ` Russell King - ARM Linux 2015-01-28 16:19 ` Will Deacon 2015-01-28 16:19 ` Will Deacon 2015-01-28 17:01 ` Russell King - ARM Linux 2015-01-28 17:01 ` Russell King - ARM Linux 2015-01-28 17:29 ` Russell King - ARM Linux 2015-01-28 17:29 ` Russell King - ARM Linux 2015-01-28 17:18 ` Pali Rohár 2015-01-28 17:18 ` Pali Rohár 2015-01-28 18:00 ` Jean-Christophe PLAGNIOL-VILLARD 2015-01-28 18:00 ` Jean-Christophe PLAGNIOL-VILLARD 2015-01-28 19:33 ` Pali Rohár 2015-01-28 19:33 ` Pali Rohár 2015-01-28 18:03 ` Pavel Machek 2015-01-28 18:03 ` Pavel Machek 2015-01-28 19:27 ` Arnd Bergmann 2015-01-28 19:27 ` Arnd Bergmann 2015-01-28 14:46 ` Jean-Christophe PLAGNIOL-VILLARD 2015-01-28 14:46 ` Jean-Christophe PLAGNIOL-VILLARD 2015-01-27 19:40 ` Nicolas Pitre 2015-01-27 19:40 ` Nicolas Pitre 2015-01-26 20:37 ` Russell King - ARM Linux 2015-01-26 20:37 ` Russell King - ARM Linux 2015-01-26 20:44 ` Pali Rohár 2015-01-26 20:44 ` Pali Rohár 2014-12-04 19:00 ` [PATCH] ARM: /proc/cpuinfo: Use DT machine name when possible Pali Rohár 2014-12-04 19:00 ` Pali Rohár 2014-12-04 10:59 ` Russell King - ARM Linux 2014-12-04 10:59 ` Russell King - ARM Linux 2014-06-18 21:10 ` Aaro Koskinen 2014-06-18 21:10 ` Aaro Koskinen 2014-07-11 19:28 ` Pavel Machek 2014-07-11 19:28 ` Pavel Machek 2014-11-24 22:21 ` Pali Rohár 2014-11-24 22:21 ` Pali Rohár 2014-09-05 11:38 ` Pali Rohár 2014-09-05 11:38 ` Pali Rohár 2014-09-05 12:13 ` Russell King - ARM Linux 2014-09-05 12:13 ` Russell King - ARM Linux 2014-09-10 12:46 ` Pavel Machek 2014-09-10 12:46 ` Pavel Machek 2014-11-24 22:23 ` Pali Rohár 2014-11-24 22:23 ` Pali Rohár 2014-09-05 13:45 ` Mark Rutland 2014-09-05 13:45 ` Mark Rutland 2014-09-05 13:52 ` Pali Rohár 2014-09-05 13:52 ` Pali Rohár 2014-09-05 13:58 ` Mark Rutland 2014-09-05 13:58 ` Mark Rutland 2014-11-24 22:25 ` Pali Rohár 2014-11-24 22:25 ` Pali Rohár 2014-09-05 13:58 ` Fabio Estevam 2014-09-05 13:58 ` Fabio Estevam 2014-11-24 22:27 ` Pali Rohár 2014-11-24 22:27 ` Pali Rohár 2014-09-06 15:34 ` Andreas Färber 2014-09-06 15:34 ` Andreas Färber 2014-11-24 22:29 ` Pali Rohár 2014-11-24 22:29 ` Pali Rohár
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