From: architt@codeaurora•org (Archit Taneja)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH V7 3/4] drm/bridge: Add driver for GE B850v3 LVDS/DP++ Bridge
Date: Thu, 2 Feb 2017 15:26:15 +0530 [thread overview]
Message-ID: <acc9dfbb-8a71-5c8c-5c22-bcbd65d5a317@codeaurora.org> (raw)
In-Reply-To: <2955-5891d280-1-64686980@191354544>
On 02/01/2017 05:51 PM, Peter Senna Tschudin wrote:
>
> 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?
The edid thing was only a suggestion. As Daniel said, it's okay to work on
it post merge.
Please do fix the minor comments I mentioned in the latest patch set. I'll
pull in the first 3 patches once Rob H gives an Ack on the DT bindings
patch. The 4th patch needs to go through the SoC maintainer.
Thanks,
Archit
>
> Yes, sure!
>
>> -Daniel
>> --
>> Daniel Vetter
>> Software Engineer, Intel Corporation
>> http://blog.ffwll.ch
>
>
>
>
>
>
--
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project
next prev parent reply other threads:[~2017-02-02 9:56 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
2017-02-02 9:56 ` Archit Taneja [this message]
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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