netdev - Re: DRM_RAS for CPER Error logging?!

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Message-ID: <aQydt0uTQBzYNzy-@intel.com>
Date: Thu, 6 Nov 2025 08:08:07 -0500
From: Rodrigo Vivi <rodrigo.vivi@...el.com>
To: Lukas Wunner <lukas@...ner.de>
CC: <dri-devel@...ts.freedesktop.org>, <intel-xe@...ts.freedesktop.org>, "Dave
 Airlie" <airlied@...il.com>, Joonas Lahtinen
	<joonas.lahtinen@...ux.intel.com>, Simona Vetter <simona.vetter@...ll.ch>,
	Hawking Zhang <Hawking.Zhang@....com>, Alex Deucher
	<alexander.deucher@....com>, Zack McKevitt
	<zachary.mckevitt@....qualcomm.com>, Aravind Iddamsetty
	<aravind.iddamsetty@...ux.intel.com>, <netdev@...r.kernel.org>, "David S.
 Miller" <davem@...emloft.net>, Eric Dumazet <edumazet@...gle.com>, "Jakub
 Kicinski" <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>, Simon Horman
	<horms@...nel.org>
Subject: Re: DRM_RAS for CPER Error logging?!

On Fri, Oct 31, 2025 at 06:38:57AM +0100, Lukas Wunner wrote:
> On Thu, Oct 30, 2025 at 10:47:18AM -0400, Rodrigo Vivi wrote:
> > On Tue, Oct 28, 2025 at 03:13:15PM -0400, Rodrigo Vivi wrote:
> > > On Mon, Sep 29, 2025 at 05:44:12PM -0400, Rodrigo Vivi wrote:
> > > 
> > > Hey Dave, Sima, AMD folks, Qualcomm folks,
> > 
> > + Netlink list and maintainers to get some feedback on the netlink usage
> > proposed here.
> > 
> > Specially to check if there's any concern with CPER blob going through
> > netlink or if there's any size limitation or concern.
> 
> How large are those blobs? 

The honest answer is: I don't know!

By spec it has no limitation, but since in general CPER is made
for FW storage it is usually not really big.

>From what I could see usual max seems to be around 64Kb. But
for our case we are looking to something much smaller than that.

> If the netlink message exceeds PAGE_SIZE
> because of the CPER blob, a workaround might be to attach it to the
> skb as fragments with skb_add_rx_frag().

Yeap, I imagined that there should be a way.

Thank you

> 
> Thanks,
> 
> Lukas