From: "Peter Senna Tschudin" <peter.senna@collabora.co.uk>
To: "Daniel Vetter" <daniel@ffwll.ch>
Cc: gregkh@linuxfoundation.org, ykk@rock-chips.com,
kernel@pengutronix.de,
"Jani Nikula" <jani.nikula@linux.intel.com>,
"Peter Senna Tschudin" <peter.senna@collabora.com>,
robh+dt@kernel.org, devicetree@vger.kernel.org,
"Fabio Estevam" <fabio.estevam@nxp.com>,
pawel.moll@arm.com, davem@davemloft.net,
martyn.welch@collabora.co.uk, enric.balletbo@collabora.com,
akpm@linux-foundation.org, martin.donnelly@ge.com,
daniel.vetter@ffwll.ch, "Archit Taneja" <architt@codeaurora.org>,
galak@codeaurora.org, linux@armlinux.org.uk, treding@nvidia.com,
tiwai@suse.com, javier@dowhile0.org, mark.rutland@arm.com,
rmk+kernel@armlinux.org.uk, dri-devel@lists.freedesktop.org,
shawnguo@kernel.org, mchehab@osg.samsung.com, jslaby@suse.cz,
ijc+devicetree@hellion.org.uk, peter.senna@gmail.com,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, linux@roeck-us.net
Subject: Re: [PATCH V7 3/4] drm/bridge: Add driver for GE B850v3 LVDS/DP++ Bridge
Date: Wed, 01 Feb 2017 12:21:01 +0000 [thread overview]
Message-ID: <2955-5891d280-1-64686980@191354544> (raw)
In-Reply-To: <20170201113536.dig22kidlw6mjoz5@phenom.ffwll.local>
On 01 February, 2017 12:35 CET, Daniel Vetter <daniel@ffwll.ch> wrote:
> 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@codeaurora.org> wrote:
> >
> > >
> > >
> > > On 01/30/2017 10:35 PM, Jani Nikula wrote:
> > > > On Sat, 28 Jan 2017, Peter Senna Tschudin <peter.senna@collabora.com> 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?
Yes, sure!
> -Daniel
> --
> Daniel Vetter
> Software Engineer, Intel Corporation
> http://blog.ffwll.ch
next prev parent reply other threads:[~2017-02-01 12:21 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
2017-01-03 22:51 ` Rob Herring
2017-01-03 23:34 ` Peter Senna Tschudin
2017-01-04 20:39 ` Rob Herring
2017-01-07 1:29 ` Peter Senna Tschudin
2017-01-10 21:04 ` Laurent Pinchart
2017-01-16 8:37 ` Peter Senna Tschudin
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
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
2017-02-01 10:58 ` Peter Senna Tschudin
2017-02-01 11:35 ` Daniel Vetter
2017-02-01 12:21 ` Peter Senna Tschudin [this message]
2017-02-02 9:56 ` Archit Taneja
2017-02-02 1:46 ` Emil Velikov
2017-02-02 11:53 ` Peter Senna Tschudin
2017-02-02 12:37 ` Emil Velikov
2017-02-03 8:00 ` Daniel Vetter
2017-02-03 12:25 ` Emil Velikov
2017-02-06 8:45 ` Daniel Vetter
2017-01-01 20:24 ` [PATCH V7 4/4] dts/imx6q-b850v3: Use " Peter Senna Tschudin
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