Re: [PATCH v2 3/4] irqchip/gic-v3: Add Renesas R-Car Gen4 erratum workaround

[Marc Zyngier <maz@kernel.org>]

On Sun, 21 Jun 2026 23:46:25 +0100,
Marek Vasut <marek.vasut@mailbox.org> wrote:
> 
> On 6/21/26 12:59 PM, Thomas Gleixner wrote:
> > On Fri, Jun 19 2026 at 00:02, Marek Vasut wrote:
> >> Renesas R-Car S4/V4H/V4M GIC600 integration has address width for AXI
> >> or APB interface configured to 32 bit, it can therefore access only
> >> the first 4 GiB of physical address space. This information comes from
> >> R-Car V4H Interface Specification sheet, there is currently no technical
> >> update number assigned to this limitation. Further input from hardware
> >> engineer indicates that this limitation also applies to R-Car S4 and V4M.
> >> Name the limitation GEN4GICITS1, and add a driver quirk to mitigate this
> >> limitation.
> >> 
> >> The quirk is keyed on the combination of the GIC implementation
> >> and the platform identification in the device tree.
> >> 
> >> Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
> >> Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
> > 
> > This SOB chain is broken.
> 
> Broken ? I don't understand , could you please elaborate ?

Either Shimoda-san is the sole author of the change and you are
posting their work, then the first line of the patch should say:

 From: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>

with your own SoB immediately following their SoB (see [1]).

Or this has been co-developed, and both of you should be credited as
authors. then Shimoda-san's SoB should be preceded by their
Co-developed-by: tag (see [2]).

 Co-developed-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
 Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
 Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>

This shows exactly who did what, who forwarded whose patch, and forms
the base of the DCO which is documented at [3].

Thanks,

	M.

[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/submitting-patches.rst#n449
[2] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/submitting-patches.rst#n503
[3] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/submitting-patches.rst#n396

-- 
Without deviation from the norm, progress is not possible.