[PATCH v2 02/38] drm/msm/dp: remove dp_display's dp_mode and use dp_panel's instead
Yongxing Mou
quic_yongmou at quicinc.com
Fri Jun 27 08:40:57 UTC 2025
On 2025/6/25 22:03, Dmitry Baryshkov wrote:
> On Wed, Jun 25, 2025 at 08:34:18PM +0800, Yongxing Mou wrote:
>>
>>
>> On 2025/6/9 20:48, Dmitry Baryshkov wrote:
>>> On Mon, Jun 09, 2025 at 08:21:21PM +0800, Yongxing Mou wrote:
>>>> From: Abhinav Kumar <quic_abhinavk at quicinc.com>
>>>>
>>>> dp_display caches the current display mode and then passes it onto
>>>> the panel to be used for programming the panel params. Remove this
>>>> two level passing and directly populated the panel's dp_display_mode
>>>> instead.
>>>
>>> - Why do we need to cache / copy it anyway? Can't we just pass the
>>> corresponding drm_atomic_state / drm_crtc_state / drm_display_mode ?
>>>
>> This part works as follows: .mode_set() copies the adjusted_mode into
>> msm_dp_display_private->msm_dp_display_mode, and also parses and stores
>> variables such as v_active_low/h_active_low/out_fmt_is_yuv_420 and ... When
>> @drm_bridge_funcs.atomic_enable() is called, it copies
>> msm_dp_display->msm_dp_mode into dp_panel->msm_dp_mode and initializes
>> panel_info in msm_dp_display_set_mode(). Then when go to
>> msm_dp_ctrl_on_stream(), the parameters are updated into the corresponding
>> hardware registers.
>
> So, if we do everything during .atomic_enable(), there would be no need
> to store and/or copy anything. All the data is available and can be used
> as is.
>
Got it. Let me confirm—can we keep msm_dp_mode or drm_display_mode in
msm_dp_panel? Mabey debug node will use this ..
>>
>> This design has been in place since the first version of the DP driver and
>> has remained largely unchanged.
>
> Yes... The point is that you are touching this piece of code anyway,
> let's make it nicer.
>
Agree with this point.
>> Originally, the drm_mode would be passed in
>> two stages: from msm_dp_display->msm_dp_mode to dp_panel->msm_dp_mode. Since
>> in MST mode each stream requires its own drm_mode and stored in dp_panel, we
>> simplified the two-stage transfer into a single step (.mode_set() do all
>> things and store in msm_dp_panel). Meanwhile we modified the
>> msm_dp_display_set_mode function to accept a msm_dp_panel parameter,
>> allowing the MST bridge funcs' mode_set() to reuse this part code.
>>
>> The following patches:
>> https://patchwork.freedesktop.org/patch/657573/?series=142207&rev=2 and
>> https://patchwork.freedesktop.org/patch/657593/?series=142207&rev=2,
>> introduce msm_dp_display_*_helper functions to help reuse common code across
>> MST/SST/eDP drm_bridge_funcs.
>>
>> If we drop msm_dp_mode from dp_panel and use drm_display_mode, it might
>> introduce a large number of changes that are not directly related to MST.
>> Actually i think the presence of msm_dp_display_mode seems to simplify the
>> work in msm_dp_panel_timing_cfg(), this patch series we want to focus on MST
>> parts, so would we consider optimizing them later?
>
> Sure... But then you have to change two places. If you optimize it
> first, you have to touch only place. And it can be even submitted
> separately.
>
Understood, that’s indeed the case. I just want to prioritize the MST
patch and have it merged first, since it involves changes to lots of
files. Thanks~~
>>
>> Thanks~
>>>>
>>>> Signed-off-by: Abhinav Kumar <quic_abhinavk at quicinc.com>
>>>> Signed-off-by: Yongxing Mou <quic_yongmou at quicinc.com>
>>>> ---
>>>> drivers/gpu/drm/msm/dp/dp_display.c | 76 ++++++++++++++-----------------------
>>>> 1 file changed, 29 insertions(+), 47 deletions(-)
>>>>
>>>> diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
>>>> index 4a9b65647cdef1ed6c3bb851f93df0db8be977af..9d2db9cbd2552470a36a63f70f517c35436f7280 100644
>>>> --- a/drivers/gpu/drm/msm/dp/dp_display.c
>>>> +++ b/drivers/gpu/drm/msm/dp/dp_display.c
>>>> @@ -92,7 +92,6 @@ struct msm_dp_display_private {
>>>> struct msm_dp_panel *panel;
>>>> struct msm_dp_ctrl *ctrl;
>>>> - struct msm_dp_display_mode msm_dp_mode;
>>>> struct msm_dp msm_dp_display;
>>>> /* wait for audio signaling */
>>>> @@ -806,16 +805,29 @@ static int msm_dp_init_sub_modules(struct msm_dp_display_private *dp)
>>>> }
>>>> static int msm_dp_display_set_mode(struct msm_dp *msm_dp_display,
>>>> - struct msm_dp_display_mode *mode)
>>>> + const struct drm_display_mode *adjusted_mode,
>>>> + struct msm_dp_panel *msm_dp_panel)
>>>> {
>>>> - struct msm_dp_display_private *dp;
>>>> + u32 bpp;
>>>> - dp = container_of(msm_dp_display, struct msm_dp_display_private, msm_dp_display);
>>>> + drm_mode_copy(&msm_dp_panel->msm_dp_mode.drm_mode, adjusted_mode);
>>>> +
>>>> + if (msm_dp_display_check_video_test(msm_dp_display))
>>>> + bpp = msm_dp_display_get_test_bpp(msm_dp_display);
>>>> + else
>>>> + bpp = msm_dp_panel->connector->display_info.bpc * 3;
>>>> +
>>>> + msm_dp_panel->msm_dp_mode.bpp = bpp;
>>>> +
>>>> + msm_dp_panel->msm_dp_mode.v_active_low =
>>>> + !!(adjusted_mode->flags & DRM_MODE_FLAG_NVSYNC);
>>>> + msm_dp_panel->msm_dp_mode.h_active_low =
>>>> + !!(adjusted_mode->flags & DRM_MODE_FLAG_NHSYNC);
>>>> + msm_dp_panel->msm_dp_mode.out_fmt_is_yuv_420 =
>>>> + drm_mode_is_420_only(&msm_dp_panel->connector->display_info, adjusted_mode) &&
>>>> + msm_dp_panel->vsc_sdp_supported;
>>>> - drm_mode_copy(&dp->panel->msm_dp_mode.drm_mode, &mode->drm_mode);
>>>> - dp->panel->msm_dp_mode.bpp = mode->bpp;
>>>> - dp->panel->msm_dp_mode.out_fmt_is_yuv_420 = mode->out_fmt_is_yuv_420;
>>>> - msm_dp_panel_init_panel_info(dp->panel);
>>>> + msm_dp_panel_init_panel_info(msm_dp_panel);
>>>> return 0;
>>>> }
>>>> @@ -1431,10 +1443,13 @@ bool msm_dp_needs_periph_flush(const struct msm_dp *msm_dp_display,
>>>> bool msm_dp_wide_bus_available(const struct msm_dp *msm_dp_display)
>>>> {
>>>> struct msm_dp_display_private *dp;
>>>> + struct msm_dp_panel *dp_panel;
>>>> dp = container_of(msm_dp_display, struct msm_dp_display_private, msm_dp_display);
>>>> - if (dp->msm_dp_mode.out_fmt_is_yuv_420)
>>>> + dp_panel = dp->panel;
>>>> +
>>>> + if (dp_panel->msm_dp_mode.out_fmt_is_yuv_420)
>>>> return false;
>>>> return dp->wide_bus_supported;
>>>> @@ -1496,10 +1511,6 @@ void msm_dp_bridge_atomic_enable(struct drm_bridge *drm_bridge,
>>>> bool force_link_train = false;
>>>> msm_dp_display = container_of(dp, struct msm_dp_display_private, msm_dp_display);
>>>> - if (!msm_dp_display->msm_dp_mode.drm_mode.clock) {
>>>> - DRM_ERROR("invalid params\n");
>>>> - return;
>>>> - }
>>>> if (dp->is_edp)
>>>> msm_dp_hpd_plug_handle(msm_dp_display, 0);
>>>> @@ -1517,15 +1528,6 @@ void msm_dp_bridge_atomic_enable(struct drm_bridge *drm_bridge,
>>>> return;
>>>> }
>>>> - rc = msm_dp_display_set_mode(dp, &msm_dp_display->msm_dp_mode);
>>>> - if (rc) {
>>>> - DRM_ERROR("Failed to perform a mode set, rc=%d\n", rc);
>>>> - mutex_unlock(&msm_dp_display->event_mutex);
>>>> - return;
>>>> - }
>>>
>>> It should be done other way around: keep this call and drop
>>> msm_dp_bridge_mode_set().
>>>
>> Emm as reply in last comments..
>
> Yep. Drop .mode_set, the callback is even described as deprecated.
>
Thanks, the documentation does state that.
>>>> -
>>>> - hpd_state = msm_dp_display->hpd_state;
>>>> -
>>>> if (hpd_state == ST_CONNECTED && !dp->power_on) {
>>>> msm_dp_display_host_phy_init(msm_dp_display);
>>>> force_link_train = true;
>>>> @@ -1604,33 +1606,13 @@ void msm_dp_bridge_mode_set(struct drm_bridge *drm_bridge,
>>>> msm_dp_display = container_of(dp, struct msm_dp_display_private, msm_dp_display);
>>>> msm_dp_panel = msm_dp_display->panel;
>>>> - memset(&msm_dp_display->msm_dp_mode, 0x0, sizeof(struct msm_dp_display_mode));
>>>> -
>>>> - if (msm_dp_display_check_video_test(dp))
>>>> - msm_dp_display->msm_dp_mode.bpp = msm_dp_display_get_test_bpp(dp);
>>>> - else /* Default num_components per pixel = 3 */
>>>> - msm_dp_display->msm_dp_mode.bpp = dp->connector->display_info.bpc * 3;
>>>> -
>>>> - if (!msm_dp_display->msm_dp_mode.bpp)
>>>> - msm_dp_display->msm_dp_mode.bpp = 24; /* Default bpp */
>>>> -
>>>> - drm_mode_copy(&msm_dp_display->msm_dp_mode.drm_mode, adjusted_mode);
>>>> -
>>>> - msm_dp_display->msm_dp_mode.v_active_low =
>>>> - !!(msm_dp_display->msm_dp_mode.drm_mode.flags & DRM_MODE_FLAG_NVSYNC);
>>>> -
>>>> - msm_dp_display->msm_dp_mode.h_active_low =
>>>> - !!(msm_dp_display->msm_dp_mode.drm_mode.flags & DRM_MODE_FLAG_NHSYNC);
>>>> -
>>>> - msm_dp_display->msm_dp_mode.out_fmt_is_yuv_420 =
>>>> - drm_mode_is_420_only(&dp->connector->display_info, adjusted_mode) &&
>>>> - msm_dp_panel->vsc_sdp_supported;
>>>> + msm_dp_display_set_mode(dp, adjusted_mode, msm_dp_panel);
>>>> /* populate wide_bus_support to different layers */
>>>> - msm_dp_display->ctrl->wide_bus_en =
>>>> - msm_dp_display->msm_dp_mode.out_fmt_is_yuv_420 ? false : msm_dp_display->wide_bus_supported;
>>>> - msm_dp_display->catalog->wide_bus_en =
>>>> - msm_dp_display->msm_dp_mode.out_fmt_is_yuv_420 ? false : msm_dp_display->wide_bus_supported;
>>>> + msm_dp_display->ctrl->wide_bus_en = msm_dp_panel->msm_dp_mode.out_fmt_is_yuv_420 ?
>>>> + false : msm_dp_display->wide_bus_supported;
>>>> + msm_dp_display->catalog->wide_bus_en = msm_dp_panel->msm_dp_mode.out_fmt_is_yuv_420 ?
>>>> + false : msm_dp_display->wide_bus_supported;
>>>> }
>>>> void msm_dp_bridge_hpd_enable(struct drm_bridge *bridge)
>>>>
>>>> --
>>>> 2.34.1
>>>>
>>>
>>
>
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