Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
MIME-Version: 1.0
References: <20200110030112.188845-1-saravanak@google.com> <CAKv+Gu-4jvME3cuPBDtTVFn+-ZzttneFuBkor+N3G0JpeO4BzA@mail.gmail.com>
In-Reply-To: <CAKv+Gu-4jvME3cuPBDtTVFn+-ZzttneFuBkor+N3G0JpeO4BzA@mail.gmail.com>
From:   Saravana Kannan <saravanak@google.com>
Date:   Fri, 10 Jan 2020 09:06:05 -0800
Message-ID: <CAGETcx9b03SBKMcN7AokSOFRfVnr9G=vzSA4p5BXnmGPQ8JjHw@mail.gmail.com>
Subject: Re: [PATCH v3] efi: arm: defer probe of PCIe backed efifb on DT systems
To:     Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc:     Ard Biesheuvel <ardb@kernel.org>,
        linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
        Will Deacon <will@kernel.org>,
        Bjorn Helgaas <bhelgaas@google.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Android Kernel Team <kernel-team@android.com>,
        linux-efi <linux-efi@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Content-Type: text/plain; charset="UTF-8"
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Thu, Jan 9, 2020 at 10:41 PM Ard Biesheuvel
<ard.biesheuvel@linaro.org> wrote:
>
> On Fri, 10 Jan 2020 at 04:01, Saravana Kannan <saravanak@google.com> wrote:
> >
> > From: Ard Biesheuvel <ardb@kernel.org>
> >
> > The new of_devlink support breaks PCIe probing on ARM platforms booting
> > via UEFI if the firmware exposes a EFI framebuffer that is backed by a
> > PCI device. The reason is that the probing order gets reversed,
> > resulting in a resource conflict on the framebuffer memory window when
> > the PCIe probes last, causing it to give up entirely.
> >
> > Given that we rely on PCI quirks to deal with EFI framebuffers that get
> > moved around in memory, we cannot simply drop the memory reservation, so
> > instead, let's use the device link infrastructure to register this
> > dependency, and force the probing to occur in the expected order.
> >
> > Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> > Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
> > Co-developed-by: Saravana Kannan <saravanak@google.com>
> > Signed-off-by: Saravana Kannan <saravanak@google.com>
> > Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
> > ---
> >
> > v1 -> v2:
> > - Rewrote the device linking part to not depend on initcall ordering
> > v2 -> v3:
> > - Added const and check for CONFIG_PCI
> >
>
> Thanks. I've queued this version in efi/next for v5.6

Awesome, thanks!

-Saravana