Re: [PATCH v1 RFC] video/hdmi: Fix HDMI_VENDOR_INFOFRAME_SIZE

From: Martin Blumenstingl
Date: Sat Feb 18 2023 - 10:34:12 EST


On Tue, Feb 14, 2023 at 10:35 PM Ville Syrjälä
<ville.syrjala@xxxxxxxxxxxxxxx> 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==HDMI_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