>>  static int
>>  skl_allocate_pipe_ddb(struct intel_crtc_state *crtc_state)
>>  {
>> @@ -4606,22 +4618,29 @@ skl_allocate_pipe_ddb(struct intel_crtc_state 
>> *crtc_state)
>>         */
>>        for (level = ilk_wm_max_level(dev_priv); level >= 0; level--) {
>>                blocks = 0;
>> +
>>                for_each_plane_id_on_crtc(crtc, plane_id) {
>> -                     const struct skl_plane_wm *wm =
>> -                             &crtc_state->wm.skl.optimal.planes[plane_id];
>> +                     const struct skl_wm_level *wm_level;
>> +                     const struct skl_wm_level *wm_uv_level;
>> +                     int color_plane = 0;

>These color_plane variables seems kinda pointless. I'd just pass 0/1 directly
>(pretty sure that's what we do elsewhere too).


Nope. I have a different view - if this is allowed here. 0/1 passed into 
function are just a magic

numbers with no meaning - that way you see at least what's the param name and 
it's meaning.


Again, _absolutely_ pointless arguing and potentially waste of time instead of 
fixing some real thing. Whether those are variables or constants, doesn't make 
this code better or worse.


>>                        /*
>>                         * We only disable the watermarks for each plane if
>> @@ -4732,9 +4765,10 @@ skl_allocate_pipe_ddb(struct intel_crtc_state 
>> *crtc_state)
>>                         *  planes must be enabled before the level will be 
>> used."
>>                         * So this is actually safe to do.
>>                         */
>> -                     if (wm->wm[level].min_ddb_alloc > total[plane_id] ||
>> -                         wm->uv_wm[level].min_ddb_alloc > 
>> uv_total[plane_id])
>> -                             memset(&wm->wm[level], 0, 
>> sizeof(wm->wm[level]));
>> +                     if (wm_level->min_ddb_alloc > total[plane_id] ||
>> +                         wm_uv_level->min_ddb_alloc > uv_total[plane_id])
>> +                             memset(&wm->wm[level], 0,
>> +                                    sizeof(struct skl_wm_level));

> memset(wm_level, 0, sizeof(*wm_level)) ?


Again - memset(wm_level, 0, sizeof(*wm_level)) and memset(wm_level, 0, 
sizeof(struct skl_wm_level)) are absolutely identical constructs according to C 
standard.

And I know that you are going to say that sizeof(*wm_level) won't require to 
change type -

well if you are changing the code anyway, this is trivial.

If I have any freedom to express my point of view at all, I'm not going to fix 
that.


Why are we even wasting time for this kind of stuff? Aren't there more serious 
problems no?

I myself have already decades of experience in coding in a rather big projects 
and big companies and can say that those kind of nitpicks are completely 
useless waste of time.



Best Regards,

Lisovskiy Stanislav
________________________________
From: Ville Syrjälä <ville.syrj...@linux.intel.com>
Sent: Wednesday, March 11, 2020 6:07:27 PM
To: Lisovskiy, Stanislav
Cc: intel-gfx@lists.freedesktop.org; Ausmus, James; Saarinen, Jani; Roper, 
Matthew D
Subject: Re: [PATCH v19 2/8] drm/i915: Introduce skl_plane_wm_level accessor.

On Mon, Mar 09, 2020 at 06:11:58PM +0200, Stanislav Lisovskiy wrote:
> For future Gen12 SAGV implementation we need to
> seemlessly alter wm levels calculated, depending
> on whether we are allowed to enable SAGV or not.
>
> So this accessor will give additional flexibility
> to do that.
>
> Currently this accessor is still simply working
> as "pass-through" function. This will be changed
> in next coming patches from this series.
>
> v2: - plane_id -> plane->id(Ville Syrjälä)
>     - Moved wm_level var to have more local scope
>       (Ville Syrjälä)
>     - Renamed yuv to color_plane(Ville Syrjälä) in
>       skl_plane_wm_level
>
> v3: - plane->id -> plane_id(this time for real, Ville Syrjälä)
>     - Changed colorplane id type from boolean to int as index
>       (Ville Syrjälä)
>     - Moved crtc_state param so that it is first now
>       (Ville Syrjälä)
>     - Moved wm_level declaration to tigher scope in
>       skl_write_plane_wm(Ville Syrjälä)
>
> Signed-off-by: Stanislav Lisovskiy <stanislav.lisovs...@intel.com>
> ---
>  drivers/gpu/drm/i915/intel_pm.c | 85 ++++++++++++++++++++++++++-------
>  1 file changed, 67 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> index c7928c870b0a..c72fa59a8302 100644
> --- a/drivers/gpu/drm/i915/intel_pm.c
> +++ b/drivers/gpu/drm/i915/intel_pm.c
> @@ -4547,6 +4547,18 @@ icl_get_total_relative_data_rate(struct 
> intel_crtc_state *crtc_state,
>        return total_data_rate;
>  }
>
> +static const struct skl_wm_level *
> +skl_plane_wm_level(const struct intel_crtc_state *crtc_state,
> +                enum plane_id plane_id,
> +                int level,
> +                int color_plane)
> +{
> +     const struct skl_plane_wm *wm =
> +             &crtc_state->wm.skl.optimal.planes[plane_id];
> +
> +     return color_plane == 0 ? &wm->wm[level] : &wm->uv_wm[level];
> +}
> +
>  static int
>  skl_allocate_pipe_ddb(struct intel_crtc_state *crtc_state)
>  {
> @@ -4606,22 +4618,29 @@ skl_allocate_pipe_ddb(struct intel_crtc_state 
> *crtc_state)
>         */
>        for (level = ilk_wm_max_level(dev_priv); level >= 0; level--) {
>                blocks = 0;
> +
>                for_each_plane_id_on_crtc(crtc, plane_id) {
> -                     const struct skl_plane_wm *wm =
> -                             &crtc_state->wm.skl.optimal.planes[plane_id];
> +                     const struct skl_wm_level *wm_level;
> +                     const struct skl_wm_level *wm_uv_level;
> +                     int color_plane = 0;

These color_plane variables seems kinda pointless. I'd just pass 0/1 directly
(pretty sure that's what we do elsewhere too).

> +
> +                     wm_level = skl_plane_wm_level(crtc_state, plane_id,
> +                                                   level, color_plane);
> +                     wm_uv_level = skl_plane_wm_level(crtc_state, plane_id,
> +                                                      level, color_plane + 
> 1);
>
>                        if (plane_id == PLANE_CURSOR) {
> -                             if (wm->wm[level].min_ddb_alloc > 
> total[PLANE_CURSOR]) {
> +                             if (wm_level->min_ddb_alloc > 
> total[PLANE_CURSOR]) {
>                                        drm_WARN_ON(&dev_priv->drm,
> -                                                 wm->wm[level].min_ddb_alloc 
> != U16_MAX);
> +                                                 wm_level->min_ddb_alloc != 
> U16_MAX);
>                                        blocks = U32_MAX;
>                                        break;
>                                }
>                                continue;
>                        }
>
> -                     blocks += wm->wm[level].min_ddb_alloc;
> -                     blocks += wm->uv_wm[level].min_ddb_alloc;
> +                     blocks += wm_level->min_ddb_alloc;
> +                     blocks += wm_uv_level->min_ddb_alloc;
>                }
>
>                if (blocks <= alloc_size) {
> @@ -4644,10 +4663,16 @@ skl_allocate_pipe_ddb(struct intel_crtc_state 
> *crtc_state)
>         * proportional to its relative data rate.
>         */
>        for_each_plane_id_on_crtc(crtc, plane_id) {
> -             const struct skl_plane_wm *wm =
> -                     &crtc_state->wm.skl.optimal.planes[plane_id];
> +             const struct skl_wm_level *wm_level;
> +             const struct skl_wm_level *wm_uv_level;
>                u64 rate;
>                u16 extra;
> +             int color_plane = 0;
> +
> +             wm_level = skl_plane_wm_level(crtc_state, plane_id,
> +                                           level, color_plane);
> +             wm_uv_level = skl_plane_wm_level(crtc_state, plane_id,
> +                                              level, color_plane + 1);
>
>                if (plane_id == PLANE_CURSOR)
>                        continue;
> @@ -4663,7 +4688,7 @@ skl_allocate_pipe_ddb(struct intel_crtc_state 
> *crtc_state)
>                extra = min_t(u16, alloc_size,
>                              DIV64_U64_ROUND_UP(alloc_size * rate,
>                                                 total_data_rate));
> -             total[plane_id] = wm->wm[level].min_ddb_alloc + extra;
> +             total[plane_id] = wm_level->min_ddb_alloc + extra;
>                alloc_size -= extra;
>                total_data_rate -= rate;
>
> @@ -4674,7 +4699,7 @@ skl_allocate_pipe_ddb(struct intel_crtc_state 
> *crtc_state)
>                extra = min_t(u16, alloc_size,
>                              DIV64_U64_ROUND_UP(alloc_size * rate,
>                                                 total_data_rate));
> -             uv_total[plane_id] = wm->uv_wm[level].min_ddb_alloc + extra;
> +             uv_total[plane_id] = wm_uv_level->min_ddb_alloc + extra;
>                alloc_size -= extra;
>                total_data_rate -= rate;
>        }
> @@ -4717,8 +4742,16 @@ skl_allocate_pipe_ddb(struct intel_crtc_state 
> *crtc_state)
>         */
>        for (level++; level <= ilk_wm_max_level(dev_priv); level++) {
>                for_each_plane_id_on_crtc(crtc, plane_id) {
> +                     const struct skl_wm_level *wm_level;
> +                     const struct skl_wm_level *wm_uv_level;
>                        struct skl_plane_wm *wm =
>                                &crtc_state->wm.skl.optimal.planes[plane_id];
> +                     int color_plane = 0;
> +
> +                     wm_level = skl_plane_wm_level(crtc_state, plane_id,
> +                                                   level, color_plane);
> +                     wm_uv_level = skl_plane_wm_level(crtc_state, plane_id,
> +                                                      level, color_plane + 
> 1);
>
>                        /*
>                         * We only disable the watermarks for each plane if
> @@ -4732,9 +4765,10 @@ skl_allocate_pipe_ddb(struct intel_crtc_state 
> *crtc_state)
>                         *  planes must be enabled before the level will be 
> used."
>                         * So this is actually safe to do.
>                         */
> -                     if (wm->wm[level].min_ddb_alloc > total[plane_id] ||
> -                         wm->uv_wm[level].min_ddb_alloc > uv_total[plane_id])
> -                             memset(&wm->wm[level], 0, 
> sizeof(wm->wm[level]));
> +                     if (wm_level->min_ddb_alloc > total[plane_id] ||
> +                         wm_uv_level->min_ddb_alloc > uv_total[plane_id])
> +                             memset(&wm->wm[level], 0,
> +                                    sizeof(struct skl_wm_level));

memset(wm_level, 0, sizeof(*wm_level)) ?

Hmm. Also wondering why we're not clearing wm_uv here as well. I suppose
it might not mater since the hw doesn't use wm_uv (and I fixed the
"did the wms change?" check to ignore it too). Bit might be nice to clear
it for consistency. Should be a separate patch though.

>
>                        /*
>                         * Wa_1408961008:icl, ehl
> @@ -4742,9 +4776,14 @@ skl_allocate_pipe_ddb(struct intel_crtc_state 
> *crtc_state)
>                         */
>                        if (IS_GEN(dev_priv, 11) &&
>                            level == 1 && wm->wm[0].plane_en) {
> -                             wm->wm[level].plane_res_b = 
> wm->wm[0].plane_res_b;
> -                             wm->wm[level].plane_res_l = 
> wm->wm[0].plane_res_l;
> -                             wm->wm[level].ignore_lines = 
> wm->wm[0].ignore_lines;
> +                             wm_level = skl_plane_wm_level(crtc_state, 
> plane_id,
> +                                                           0, color_plane);
> +                             wm->wm[level].plane_res_b =
> +                                     wm_level->plane_res_b;
> +                             wm->wm[level].plane_res_l =
> +                                     wm_level->plane_res_l;
> +                             wm->wm[level].ignore_lines =
> +                                     wm_level->ignore_lines;

I would suggest we want this to read something like:

const struct skl_wm_level *wm_level0 = skl_plane_wm_level(...)

wm_level->foo = wm_level0->foo;
...

And with those we can throw out the 'wm' variable from this loop as
well.

>                        }
>                }
>        }
> @@ -5358,8 +5397,13 @@ void skl_write_plane_wm(struct intel_plane *plane,
>                &crtc_state->wm.skl.plane_ddb_uv[plane_id];
>
>        for (level = 0; level <= max_level; level++) {
> +             const struct skl_wm_level *wm_level;
> +             int color_plane = 0;
> +
> +             wm_level = skl_plane_wm_level(crtc_state, plane_id, level, 
> color_plane);
> +
>                skl_write_wm_level(dev_priv, PLANE_WM(pipe, plane_id, level),
> -                                &wm->wm[level]);
> +                                wm_level);
>        }
>        skl_write_wm_level(dev_priv, PLANE_WM_TRANS(pipe, plane_id),
>                           &wm->trans_wm);
> @@ -5392,8 +5436,13 @@ void skl_write_cursor_wm(struct intel_plane *plane,
>                &crtc_state->wm.skl.plane_ddb_y[plane_id];
>
>        for (level = 0; level <= max_level; level++) {
> +             const struct skl_wm_level *wm_level;
> +             int color_plane = 0;
> +
> +             wm_level = skl_plane_wm_level(crtc_state, plane_id, level, 
> color_plane);
> +
>                skl_write_wm_level(dev_priv, CUR_WM(pipe, level),
> -                                &wm->wm[level]);
> +                                wm_level);
>        }
>        skl_write_wm_level(dev_priv, CUR_WM_TRANS(pipe), &wm->trans_wm);
>
> --
> 2.24.1.485.gad05a3d8e5

--
Ville Syrjälä
Intel
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