Mailinglist Archive: radeonhd (436 mails)

["Alex Deucher" <alexdeucher@xxxxxxxxx>]

On Tue, Jul 22, 2008 at 4:03 AM, Luc Verhaegen <libv@xxxxxxxxx> wrote:
> On Mon, Jul 21, 2008 at 06:20:17PM -0400, Alex Deucher wrote:
> > On Mon, Jul 21, 2008 at 6:07 PM, Sven Lankes <sven@xxxxxxx> wrote:
> > > On Mon, Jul 21, 2008 at 11:53:01PM +0200, Luc Verhaegen wrote:
> > >
> > > > > This looks like TMDSA load detection not working.
> > > > > Luc, can you look into this when you find the time?
> > >
> > > > You will find that, when you run rhd_conntest, the monitor only at
> > > > certain times puts loads on the digital lines. We have seen the same
> > > > problem with some other monitors...
> > >
> > > This is a Dell 24" - pretty common I'd say.
> > >
> > > > So it is a problem with not the TMDSA load detection, but with the
> > > > monitor attached to it, and a suitable strategy still needs to be
> > > > proposed here.
> > >
> > > Pardon my ignorance but how does the radeon-driver handle this?
> >
> > radeon uses ddc to detect the presence of a monitor, and then (for
> > DACs at least) falls back to load detection if ddc fails.
> >
> > Alex
>
> How do you distinguish between the DAC and TMDS parts on DVI connectors
> then?

We check the digital bit in the edid if the connector is DVI-I.  if
it's digitial, it's TMDS, otherwise, it's DAC.

> Also, hpd, with some quirks for the cards that, even though the hardware
> was there and is solid, didn't provide any HPD information through
> atombios (R5xx), tends to be rather solid.

Right, at least on r5xx cards, the hpd information in the bios is not
always reliable, but the ddc i2c info is.

> DDC has proven to be a gamble as well, as monitor manufacturers aren't
> as great as ATI is at making hardware.

I realize ddc isn't always reliable, but it seems to work more
reliably than load detection in my experience.

Alex
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