[Intel-gfx] [PATCH v3 0/4] Enable lspcon support for GEN9 devices

[Sharma, Shashank]

Hi Ville.

> This thing seems to be missing a lot of stuff:
> - where is the EDID etc. handling?
None required for LSPCON as of now. The 4k at 60 pixel clock support was already added with SKL, so we can see
a HDMI 4k at 60 output already on PCON mode, when connected to a 4k at 60 monitor.

I have started publishing a separate patch series to support HDMI 2.0, started with the new aspect ratio patches here. I was hoping to proceed with EDID changes, once we get these in, else the patch series gets huge and reviewers find it difficult to review. 
https://patchwork.freedesktop.org/patch/78308/ 
 
Plan is to publish in this sequence:
- Add new aspect ratios
- Add new 4k modes in DRM EDID
- Add Scrambling support
- Add SCDC parsing
- Add YUV 420 CEA-861-F block parsing
and so on. 

> - based on my DDI output_types stuff, I was expecting to see an
>  lspcon .compute_output_type() hook that returns whether we need
 >  LS or PCON mode. Can't see anything of the sort here.
As I explained in the commit message/cover letter LSPCON is no more working selectively on LS/PCON mode.
We are driving it in always PCON mode, and driver always drives a DP.  So we are driving a DP with separate detection sequence. 

> Also the main patch [1] of my DDI output_types series still didn't get reviewed...
Ok, but that should not be a blocker for this series, should it ? 

Regards
Shashank
-----Original Message-----
From: Ville Syrjälä [mailto:ville.syrjala at linux.intel.com] 
Sent: Wednesday, July 20, 2016 6:39 PM
To: Sharma, Shashank <shashank.sharma at intel.com>
Cc: intel-gfx at lists.freedesktop.org; rodrigo.vivi at gmail.com; Vivi, Rodrigo <rodrigo.vivi at intel.com>; Zanoni, Paulo R <paulo.r.zanoni at intel.com>
Subject: Re: [PATCH v3 0/4] Enable lspcon support for GEN9 devices

On Tue, Jul 05, 2016 at 06:35:46PM +0530, Shashank Sharma wrote:
> LSPCON is essentially a dp++->hdmi adapter with dual mode of operation.
> 
> These modes are:
> - Level Shifter mode: In LS mode, this device works as a type2 
> dp->hdmi passive dongle, which steps up DP++ output to appropriate HDMI 1.4 signal.
> This mode doesn't do any conversion at the protocol level.
> 
> - Protocol Converter mode: In PCON mode, this device acts as an active 
> DP++->HDMI 2.0 dongle, which converts the DP++ output to compatible 
> HDMI 2.0 output. In PCON mode, lspcon can support 4k at 60 outputs, using 
> DP HBR2 mode.
> 
> Many of Intel GEN9 devices come with in-built lspcon card in 
> motherboartd down mode. This patch series adds support for lspcon 
> devices in I915 driver.
> 
> While unit-testing this code, I was able to see a 4k at 60 modeset with:
> - BXT-T board
> - Single HDMI 4k at 60 display (ACER S)
> - Ubuntu 14.04 desktop
> 
> V2: Worked on review comments from Ville
> - In general, Ville suggested not to use the dual personality of
>   DDI to drive lspcon, so this patch set drives it just as DP++ display.
>   There is no separate detection for lspcon (hpd_pulse is good enough), and
>   its being driven as a DP display with special initialization and EDID
>   read sequence. To be able to do this, we driving lspcon in PCON mode only,
>   where it can serve both HDMI1.3/HDMI1.4 sinks as well as 4k at 60 capable
>   HDMI 2.0 sinks. So compared to previous series, there is one patch less,
>   as we have dropped lspcon detection patch.
> 
> 
> V3: Addressed review comments from Rodrigo
>     Details available in respective patch.
> 
> Shashank Sharma (4):
>   drm: Helper for lspcon in drm_dp_dual_mode
>   drm/i915: Add lspcon support for I915 driver
>   drm/i915: Parse VBT data for lspcon
>   drm/i915: Enable lspcon initialization

This thing seems to be missing a lot of stuff:
- where is the EDID etc. handling?
None required for LSPCON as of now. The 4k at 60 pixel clock support was already added with SKL
- based on my DDI output_types stuff, I was expecting to see an
  lspcon .compute_output_type() hook that returns whether we need
  LS or PCON mode. Can't see anything of the sort here.

Also the main patch [1] of my DDI output_types series still didn't get reviewed...

[1] https://patchwork.freedesktop.org/patch/94581/

> 
>  drivers/gpu/drm/drm_dp_dual_mode_helper.c | 103 +++++++++++++++++++++
>  drivers/gpu/drm/i915/Makefile             |   1 +
>  drivers/gpu/drm/i915/i915_drv.h           |   5 ++
>  drivers/gpu/drm/i915/intel_bios.c         |  49 ++++++++++
>  drivers/gpu/drm/i915/intel_ddi.c          |  29 +++++-
>  drivers/gpu/drm/i915/intel_drv.h          |  13 ++-
>  drivers/gpu/drm/i915/intel_lspcon.c       | 145 ++++++++++++++++++++++++++++++
>  include/drm/drm_dp_dual_mode_helper.h     |  26 ++++++
>  8 files changed, 369 insertions(+), 2 deletions(-)  create mode 
> 100644 drivers/gpu/drm/i915/intel_lspcon.c
> 
> --
> 1.9.1

--
Ville Syrjälä
Intel OTC