MIME-Version: 1.0
References: <20230109223110.1165433-1-martin.blumenstingl@googlemail.com>
 <Y+DPQjukgC0BELkN@intel.com> <CAFBinCBpbRu9xfCEfZJfT7t3doV=+CX03+h7W+HsoW5T4X0W0w@mail.gmail.com>
 <Y+oa6O6+s5UXvOP6@intel.com> <CAFBinCC6RRiN0=XYNw464omzjHrRcNZn39i3_Ztfq6M2xMpgRw@mail.gmail.com>
 <Y+v+jFKiQ3Rj2aYL@intel.com>
In-Reply-To: <Y+v+jFKiQ3Rj2aYL@intel.com>
From:   Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Date:   Sat, 18 Feb 2023 16:33:56 +0100
Message-ID: <CAFBinCARqY5K6r_9WcKvBnVfUJuFv78ZYk6D0UiA7FYaA4Kkog@mail.gmail.com>
Subject: Re: [PATCH v1 RFC] video/hdmi: Fix HDMI_VENDOR_INFOFRAME_SIZE
To:     =?UTF-8?B?VmlsbGUgU3lyasOkbMOk?= <ville.syrjala@linux.intel.com>
Cc:     dri-devel@lists.freedesktop.org, Helge Deller <deller@gmx.de>,
        linux-fbdev@vger.kernel.org, linux-kernel@vger.kernel.org,
        Hans Verkuil <hans.verkuil@cisco.com>,
        Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>,
        Bernard Zhao <bernard@vivo.com>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
Precedence: bulk

On Tue, Feb 14, 2023 at 10:35 PM Ville Syrj=C3=A4l=C3=A4
<ville.syrjala@linux.intel.com> wrote:
[...]
> > > We should perhaps just get rid of HDMI_VENDOR_INFOFRAME_SIZE
> > > entirely.
> > My thought was to make it the correct size for
> > drm_hdmi_vendor_infoframe_from_display_mode(). Then developers using
> > this "common" vendor infoframe don't have to worry much.
> > If there's another vendor infoframe implementation (which I'm not
> > aware of, but it may exist - since as you point out: it's vendor
> > specific) then the driver code shouldn't use
> > drm_hdmi_vendor_infoframe_from_display_mode() but rather implement
> > something custom. At that point the person implementing that will also
> > need to know their specific infoframe maximum size.
>
> Yes but that other infoframe will still have
> type=3D=3DHDMI_INFOFRAME_TYPE_VENDOR, and
> HDMI_INFOFRAME_SIZE(VENDOR) would again
> give the wrong answer.
So this means the way forward is to remove HDMI_VENDOR_INFOFRAME_SIZE?
That means it's up to the (HDMI) driver developers to use a big enough
buffer (by hard-coding the size). Last time I checked all drivers did.


Best regards,
Martin