Messages in this thread | | | From | Keith Packard <> | Subject | Re: [Intel-gfx] [PATCH 6/7] drm/i915: Disable FDI RX before FDI TX | Date | Fri, 17 Aug 2012 16:10:57 -0700 |
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"Lespiau, Damien" <damien.lespiau@intel.com> writes:
> I can't see anything in the docs about an order requirement for those.
Right, the docs don't say anything, which is a bit disconcerting.
> Not sure why the other way does not make sense. Somehow disabling TX > before RX makes some sense to me (TX enabled without a ready RX looks > weird?, no data should flow as the pipe is shutdown at that point > anyway). Maybe it just does not matter?
And here I figured disabling RX before TX made more sense -- otherwise the receiver wouldn't be seeing anything. In other areas of the driver, we're careful to disable receivers before senders (disable CRTC before PLL, etc).
> Another detail is that disabling the PLLs seem to have an order in the > disabling sequence, TX, then RX. > > I. Disable CPU FDI Transmitter PLL > II. Disable PCH FDI Receiver PLL
That ordering doesn't matter as the FDI receiver and transmitter are both disabled by that point, so they aren't talking at all.
-- keith.packard@intel.com [unhandled content-type:application/pgp-signature] | |