Messages in this thread |  | | From | Doug Anderson <> | Date | Mon, 16 Dec 2019 16:31:16 -0800 | Subject | Re: [PATCH 9/9] drm/bridge: ti-sn65dsi86: Skip non-standard DP rates |
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Hi,
On Sun, Dec 15, 2019 at 5:19 PM Jeffrey Hugo <jeffrey.l.hugo@gmail.com> wrote: > > On Fri, Dec 13, 2019 at 5:49 PM Doug Anderson <dianders@chromium.org> wrote: > > > > Hi, > > > > On Fri, Dec 13, 2019 at 4:07 PM Daniel Vetter <daniel@ffwll.ch> wrote: > > > > > > On Fri, Dec 13, 2019 at 03:45:30PM -0800, Douglas Anderson wrote: > > > > The bridge chip supports these DP rates according to TI's spec: > > > > * 1.62 Gbps (RBR) > > > > * 2.16 Gbps > > > > * 2.43 Gbps > > > > * 2.7 Gbps (HBR) > > > > * 3.24 Gbps > > > > * 4.32 Gbps > > > > * 5.4 Gbps (HBR2) > > > > > > > > As far as I can tell, only RBR, HBR, and HBR2 are part of the DP spec. > > > > If other rates work then I believe it's because the sink has allowed > > > > bending the spec a little bit. > > > > > > I think you need to look at the eDP spec. And filter this stuff correctly > > > (there's more fields there for these somewhat irky edp timings). Simply > > > not using them works, but it's defeating the point of having these > > > intermediate clocks for edp panels. > > > > Ah, I see my problem. I had earlier only found the eDP 1.3 spec which > > doesn't mention these rates. The eDP 1.4 spec does, however. ...and > > the change log for 1.4 specifically mentions that it added 4 new link > > rates and also adds the "SUPPORTED_LINK_RATES" register. > > Yeah, you need the eDP spec. I previously posted > https://patchwork.kernel.org/patch/11205201/ and was hoping Bjorn > would find time to test it. Maybe it would fit well with your series? > I'm coming back from tracel, and hope to review everything you have, > but this caught my eye.
Ah, interesting. It looks like Rob has already posted a Fixup on my patch:
https://lore.kernel.org/r/20191215200632.1019065-1-robdclark@gmail.com
...that should also read the supported rates. I need to go and review / test his new patch (I lost access to the hardware but should get it back tomorrow or the next day), but would you be OK with going that route? I think my series is a superset of yours. Specifically it has these extra features atop yours:
* If link training fails and the panel supports faster rates, it will try a faster rate in case it works.
* It adds support for using 6bpp when that's all that's needed, reducing bandwidth to the panel (and link rate)
* It breaks things into smaller functions (assuming you agree this is a good thing).
-Doug
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