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From: Greg KH <greg@kroah.com>
To: "Pali Rohár" <pali@kernel.org>
Cc: Aurelien Jarno <aurelien@aurel32.net>,
	Florian Fainelli <florian.fainelli@broadcom.com>,
	stable@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: Backporting commits for generating rpi dtb symbols to stable
Date: Sun, 16 Jul 2023 18:32:42 +0200	[thread overview]
Message-ID: <2023071644-earflap-amazingly-3989@gregkh> (raw)
In-Reply-To: <20230716162444.zzvkm4rh7s7lu37x@pali>

On Sun, Jul 16, 2023 at 06:24:44PM +0200, Pali Rohár wrote:
> Hello,
> 
> I see that raspberry pi bootloader throws ton of warnings when supplied
> DTB file does not contain /__symbols__/ node.
> 
> On RPI 1B rev1 it looks like this:
> 
> dterror: no symbols found
> dterror: no symbols found
> dterror: no symbols found
> dterror: no symbols found
> dterror: no symbols found
> dterror: no symbols found
> dterror: no symbols found
> dterror: no symbols found
> dterror: no symbols found
> dterror: no symbols found
> 
> Bootloader also propagates these warnings to kernel via dtb property
> chosen/user-warnings and they can be read by simple command:
> 
> $ cat /sys/firmware/devicetree/base/chosen/user-warnings
> ...
> 
> Upstream Linux kernel build process by default does not generate
> /__symbols__/ node for DTB files, but DTB files provided by raspberrypi
> foundation have them for a longer time.
> 
> I wanted to look at this issue, but I figured out that it is already
> solved by just recent Aurelien's patches:
> 
> e925743edc0d ("arm: dts: bcm: Enable device-tree overlay support for RPi devices")
> 3cdba279c5e9 ("arm64: dts: broadcom: Enable device-tree overlay support for RPi devices")
> 
> My testing showed that /__symbols__/ node is required by rpi bootloader
> for overlay support even when overlayed DTB file does not use any DTB
> symbol (and reference everything via full node path). So seems that
> /__symbols__/ node is crucial for rpi bootloader even when symbols from
> them are not used at all.
> 
> So I would like to ask, would you consider backporting these two
> raspberry pi specific patches to stable kernel trees? Upstream kernel
> would get rid of those bootloader warnings and also allow users to use
> overlayed dtbs...

What kernel tree(s) should these be applied to?  What trees did you test
them for?

Also, adding dt-overlay support does not seem like a stable kernel fix,
as this isn't a bugfix from what I can tell, right?

thanks,

greg k-h

  reply	other threads:[~2023-07-16 16:32 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-07-16 16:24 Backporting commits for generating rpi dtb symbols to stable Pali Rohár
2023-07-16 16:32 ` Greg KH [this message]
2023-07-16 16:38   ` Pali Rohár
2023-07-16 19:08     ` Greg KH
2023-07-16 19:51       ` Pali Rohár
2023-07-17 10:38         ` Florian Fainelli
2023-07-16 19:47 ` Aurelien Jarno
2023-07-16 19:55   ` Pali Rohár

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