From: Daniel Vetter <daniel-/w4YWyX8dFk@public.gmane.org>
To: Peter Senna Tschudin
<peter.senna-ZGY8ohtN/8pPYcu2f3hruQ@public.gmane.org>
Cc: Archit Taneja <architt-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>,
ijc+devicetree-KcIKpvwj1kUDXYZnReoRVg@public.gmane.org,
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Peter Senna Tschudin
<peter.senna-ZGY8ohtN/8qB+jHODAdFcQ@public.gmane.org>,
tiwai-IBi9RG/b67k@public.gmane.org,
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enric.balletbo-ZGY8ohtN/8qB+jHODAdFcQ@public.gmane.org, dri-
Subject: Re: [PATCH V7 3/4] drm/bridge: Add driver for GE B850v3 LVDS/DP++ Bridge
Date: Wed, 1 Feb 2017 12:35:36 +0100 [thread overview]
Message-ID: <20170201113536.dig22kidlw6mjoz5@phenom.ffwll.local> (raw)
In-Reply-To: <64ff-5891bf80-f-117f65c0@159002012>
On Wed, Feb 01, 2017 at 10:58:43AM +0000, Peter Senna Tschudin wrote:
> Hi Archit,
>
> On 01 February, 2017 10:44 CET, Archit Taneja <architt-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org> wrote:
>
> >
> >
> > On 01/30/2017 10:35 PM, Jani Nikula wrote:
> > > On Sat, 28 Jan 2017, Peter Senna Tschudin <peter.senna-ZGY8ohtN/8qB+jHODAdFcQ@public.gmane.org> wrote:
> > >> On Thu, Jan 05, 2017 at 01:18:47PM +0530, Archit Taneja wrote:
> > >> Hi Archit,
> > >>
> > >> Thank you for the comments!
> > >>
> > >> [...]
> > >>>> + total_size = (block[EDID_EXT_BLOCK_CNT] + 1) * EDID_LENGTH;
> > >>>> + if (total_size > EDID_LENGTH) {
> > >>>> + kfree(block);
> > >>>> + block = kmalloc(total_size, GFP_KERNEL);
> > >>>> + if (!block)
> > >>>> + return NULL;
> > >>>> +
> > >>>> + /* Yes, read the entire buffer, and do not skip the first
> > >>>> + * EDID_LENGTH bytes.
> > >>>> + */
> > >>>
> > >>> Is this the reason why you aren't using drm_do_get_edid()?
>
> > >>
> > >> Yes, for some hw specific reason, it is necessary to read the entire
> > >> EDID buffer starting from 0, not block by block.
> > >
> > > Hrmh, I'm planning on moving the edid override and firmware edid
> > > mechanisms at the drm_do_get_edid() level to be able to truly and
> > > transparently use a different edid. Currently, they're only used for
> > > modes, really, and lead to some info retrieved from overrides, some from
> > > the real edid. This kind of hacks will bypass the override/firmware edid
> > > mechanisms then too. :(
> >
> > It seems like there is a HW issue which prevents them from reading EDID
> > from an offset. So, I'm not sure if it is a hack or a HW limitation.
>
> >
> > One way around this would be to hide the HW requirement in the
> > get_edid_block func pointer passed to drm_do_get_edid(). This
> > would, however, result in more i2c reads (equal to # of extension
> > blocks) than what the patch currently does.
> >
> > Peter, if you think doing extra EDID reads isn't too costly on your
> > platform, you could consider using drm_do_get_edid(). If not, I guess
> > you'll miss out on the additional functionality Jani is going to add
>
> > in the future.
>
> My concern is that for almost one year now, every time I fix something
> one or two new requests are made. I'm happy to fix the driver, but I
> want a list of the changes that are required to get it upstream, before
> I make more changes. Can we agree on exactly what is preventing this
> driver to get upstream? Then I'll fix it.
I think addressing this edid reading question post-merge is perfectly
fine. Aside, want to keep maintaing your stuff as part of the drm-misc
group, with the drivers-in-misc experiment?
-Daniel
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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next prev parent reply other threads:[~2017-02-01 11:35 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-01 20:24 [PATCH V7 0/4] Add driver for GE B850v3 LVDS/DP++ Bridge Peter Senna Tschudin
2017-01-01 20:24 ` [PATCH V7 1/4] Documentation/devicetree/bindings: b850v3_lvds_dp Peter Senna Tschudin
[not found] ` <21ea1b0795bdaa30ca475d6ce675b620b2b644ed.1483301745.git.peter.senna-ZGY8ohtN/8qB+jHODAdFcQ@public.gmane.org>
2017-01-03 22:51 ` Rob Herring
2017-01-03 23:34 ` Peter Senna Tschudin
2017-01-04 20:39 ` Rob Herring
[not found] ` <CAL_JsqJk=QZ20VmV5uE1ta2T0TEO3rvWFbiGsJpH1e3-ojnBfA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-01-07 1:29 ` Peter Senna Tschudin
2017-01-10 21:04 ` Laurent Pinchart
2017-01-16 8:37 ` Peter Senna Tschudin
[not found] ` <20170116083711.GA18775-ZGY8ohtN/8qB+jHODAdFcQ@public.gmane.org>
2017-01-18 21:10 ` Laurent Pinchart
2017-01-19 8:12 ` Peter Senna Tschudin
2017-01-19 8:17 ` Laurent Pinchart
2017-01-19 9:25 ` Peter Senna Tschudin
2017-01-19 11:49 ` Laurent Pinchart
2017-01-10 21:06 ` Laurent Pinchart
2017-01-01 20:24 ` [PATCH V7 2/4] MAINTAINERS: Add entry for GE B850v3 LVDS/DP++ Bridge Peter Senna Tschudin
2017-01-01 20:24 ` [PATCH V7 3/4] drm/bridge: Add driver " Peter Senna Tschudin
[not found] ` <4232c88a99f44a24287d04d74b891e2eb139864c.1483301745.git.peter.senna-ZGY8ohtN/8qB+jHODAdFcQ@public.gmane.org>
2017-01-02 11:26 ` Peter Senna Tschudin
2017-01-05 7:48 ` Archit Taneja
2017-01-28 14:16 ` Peter Senna Tschudin
2017-01-30 17:05 ` Jani Nikula
2017-02-01 9:44 ` Archit Taneja
[not found] ` <b84ac3b8-3626-3eb2-7293-0affb58b7752-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>
2017-02-01 10:58 ` Peter Senna Tschudin
2017-02-01 11:35 ` Daniel Vetter [this message]
2017-02-01 12:21 ` Peter Senna Tschudin
2017-02-02 9:56 ` Archit Taneja
2017-02-02 1:46 ` Emil Velikov
[not found] ` <cover.1483301745.git.peter.senna-ZGY8ohtN/8qB+jHODAdFcQ@public.gmane.org>
2017-01-01 20:24 ` [PATCH V7 4/4] dts/imx6q-b850v3: Use " Peter Senna Tschudin
[not found] <CACvgo535iyFvdOWzQHRnU++Ye0GgyZyN3R9ALSXRP7k3EPyRGA@mail.gmail.com>
2017-02-02 11:53 ` [PATCH V7 3/4] drm/bridge: Add driver for " Peter Senna Tschudin
2017-02-02 12:37 ` Emil Velikov
[not found] ` <CACvgo50bOZ=jzeJc_J4_7fpiEh9-ATKo1KOhAia2679AGA=mng-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-02-03 8:00 ` Daniel Vetter
[not found] ` <20170203080040.qn53xnpojxzk4qoi-dv86pmgwkMBes7Z6vYuT8azUEOm+Xw19@public.gmane.org>
2017-02-03 12:25 ` Emil Velikov
[not found] ` <CACvgo53BpgFwr3-LRhe8QpvD3ZRMr7huaRKyp5PTAY6O60J3xA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-02-06 8:45 ` Daniel Vetter
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