[PATCH 0/4] drm/edid & drm/i915: vendor and product id logging improvements

[Melissa Wen]

On 04/08, Jani Nikula wrote:
> On Mon, 08 Apr 2024, Melissa Wen <mwen at igalia.com> wrote:
> > On 04/02, Jani Nikula wrote:
> >> On Thu, 21 Mar 2024, Jani Nikula <jani.nikula at intel.com> wrote:
> >> > Jani Nikula (4):
> >> >   drm/edid: add drm_edid_get_product_id()
> >> >   drm/edid: add drm_edid_print_product_id()
> >> >   drm/i915/bios: switch to struct drm_edid and struct
> >> >     drm_edid_product_id
> >> >   drm/i915/bios: return drm_edid_product_id from get_lvds_pnp_id()
> >> 
> >> Ping for reviews please? This should be helpful in eradicating one class
> >> of drm_edid_raw() uses.
> >
> > Hi Jani,
> >
> > I took a look at the series. AFAIU your solution with
> > `drm_edid_product_id` mostly fits AMD display driver needs, except that
> > it needs the `product_code` split into two parts (like manufacturer
> > name) because the driver handles prod_code parts to configure a register
> > for audio, as in the path below:
> >
> > 1. https://gitlab.freedesktop.org/drm/kernel/-/blob/drm-next/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c#L113
> > 2. https://gitlab.freedesktop.org/drm/kernel/-/blob/drm-next/drivers/gpu/drm/amd/display/dc/core/dc_stream.c#L90
> > 3. https://gitlab.freedesktop.org/drm/kernel/-/blob/drm-next/drivers/gpu/drm/amd/display/dc/dce/dce_audio.c#L873
> >
> > What do you think on keeping `prod_code` split into two part in
> > `drm_edid_product_id`?
> 
> I think having it as "__le16 product_code" is better and
> self-documenting. This is what the spec says it is, so why split it to
> two parts where you always need to wonder about the byte order?

I have no strong opinion, I was only thinking that two parts would make
this `edid_buf->prod_code[0] | edid_buf->prod_code[1] << 8` operation
more intuitive.

As you mentioned the currrent product_code format fits specs better, I
understand we can get the same result on amd with:
le16_to_cpu() --> split --> second part shift.

Anyway, it's certainly not a blocker. The series LGTM.

Acked-by: Melissa Wen <mwen at igalia.com>

> 
> This is how you'd use it:
> 
> 	edid_caps->product_id = le16_to_cpu(id->product_code);
> 
> BR,
> Jani.
> 
> >
> > (cc'ing some AMD devs that might have a better understanding of this use case)
> >
> > Thanks a lot for addressing this pending issue!
> >
> > Melissa
> >
> >> 
> >> BR,
> >> Jani.
> >> 
> >> 
> >> >
> >> >  drivers/gpu/drm/drm_edid.c                | 50 +++++++++++++++++++++++
> >> >  drivers/gpu/drm/i915/display/intel_bios.c | 49 ++++++++++------------
> >> >  include/drm/drm_edid.h                    | 28 ++++++++++---
> >> >  3 files changed, 94 insertions(+), 33 deletions(-)
> >> 
> >> -- 
> >> Jani Nikula, Intel
> 
> -- 
> Jani Nikula, Intel