Date:   Mon, 3 Jan 2022 07:11:27 +0100
From:   Gerd Hoffmann <kraxel@redhat.com>
To:     Niklas Schnelle <schnelle@linux.ibm.com>
Cc:     Arnd Bergmann <arnd@kernel.org>,
        Bjorn Helgaas <bhelgaas@google.com>,
        John Garry <john.garry@huawei.com>,
        Nick Hu <nickhu@andestech.com>,
        Greentime Hu <green.hu@gmail.com>,
        Vincent Chen <deanbo422@gmail.com>,
        Paul Walmsley <paul.walmsley@sifive.com>,
        Palmer Dabbelt <palmer@dabbelt.com>,
        Albert Ou <aou@eecs.berkeley.edu>, Guo Ren <guoren@kernel.org>,
        Dave Airlie <airlied@redhat.com>,
        David Airlie <airlied@linux.ie>,
        Daniel Vetter <daniel@ffwll.ch>, linux-kernel@vger.kernel.org,
        linux-arch@vger.kernel.org, linux-pci@vger.kernel.org,
        linux-riscv@lists.infradead.org, linux-csky@vger.kernel.org,
        virtualization@lists.linux-foundation.org,
        spice-devel@lists.freedesktop.org, dri-devel@lists.freedesktop.org
Subject: Re: [RFC 26/32] drm: handle HAS_IOPORT dependencies
Message-ID: <20220103061127.jrnsfuxbxk2ywmtg@sirius.home.kraxel.org>
References: <20211227164317.4146918-1-schnelle@linux.ibm.com>
 <20211227164317.4146918-27-schnelle@linux.ibm.com>
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On Mon, Dec 27, 2021 at 05:43:11PM +0100, Niklas Schnelle wrote:
> In a future patch HAS_IOPORT=n will result in inb()/outb() and friends
> not being declared. We thus need to add HAS_IOPORT as dependency for
> those drivers using them. There is also a direct and hard coded use in
> cirrus.c which according to the comment is only necessary during resume.
> Let's just skip this as for example s390 which doesn't have I/O port
> support also doesen't support suspend/resume.

>  config DRM_BOCHS
>  	tristate "DRM Support for bochs dispi vga interface (qemu stdvga)"
>  	depends on DRM && PCI && MMU
> +	depends on HAS_IOPORT
>  	select DRM_KMS_HELPER
>  	select DRM_VRAM_HELPER
>  	select DRM_TTM

On devices with an mmio bar the driver works just fine without inb/outb,
see bochs->mmio checks in bochs.c

take care,
  Gerd