Aw: Re: BUG: MTK DRM/HDMI broken on 5.13 (mt7623/bpi-r2)

[Dafna Hirschfeld]

Hi

On 08.07.21 11:35, Frank Wunderlich wrote:
> Hi
> 
> just a small update, added debug in the vendor-specific functions for page_flip and vblank and it seems they never get called
> 
> --- a/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
> +++ b/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
> @@ -87,21 +87,25 @@ static void mtk_drm_crtc_finish_page_flip(struct mtk_drm_crtc *mtk_crtc)
>   {
>          struct drm_crtc *crtc = &mtk_crtc->base;
>          unsigned long flags;
> -
> +printk(KERN_ALERT "DEBUG: Passed %s %d \n",__FUNCTION__,__LINE__);
>          spin_lock_irqsave(&crtc->dev->event_lock, flags);
>          drm_crtc_send_vblank_event(crtc, mtk_crtc->event);
>          drm_crtc_vblank_put(crtc);
>          mtk_crtc->event = NULL;
>          spin_unlock_irqrestore(&crtc->dev->event_lock, flags);
> +printk(KERN_ALERT "DEBUG: Passed %s %d \n",__FUNCTION__,__LINE__);
>   }
> 
>   static void mtk_drm_finish_page_flip(struct mtk_drm_crtc *mtk_crtc)
>   {
> +printk(KERN_ALERT "DEBUG: Passed %s %d update:%d,needsvblank:%d\n",__FUNCTION__,__LINE__,mtk_crtc->config_updating,mtk_crtc->pending_needs_vblank);
>          drm_crtc_handle_vblank(&mtk_crtc->base);
>          if (!mtk_crtc->config_updating && mtk_crtc->pending_needs_vblank) {
> +printk(KERN_ALERT "DEBUG: Passed %s %d \n",__FUNCTION__,__LINE__);
>                  mtk_drm_crtc_finish_page_flip(mtk_crtc);
>                  mtk_crtc->pending_needs_vblank = false;
>          }
> +printk(KERN_ALERT "DEBUG: Passed %s %d \n",__FUNCTION__,__LINE__);
>   }
> 
>   static void mtk_drm_crtc_destroy(struct drm_crtc *crtc)
> 
> finish_page_flip is called by mtk_crtc_ddp_irq. this seems to be set in mtk_drm_crtc_enable_vblank with mtk_ddp_comp_enable_vblank. this is called correctly
> 
> 113 static inline void mtk_ddp_comp_enable_vblank(struct mtk_ddp_comp *comp,
> 114                           void (*vblank_cb)(void *),
> 115                           void *vblank_cb_data)
> 116 {
> 117 printk(KERN_ALERT "DEBUG: Passed %s %d \n",__FUNCTION__,__LINE__);
> 118     if (comp->funcs && comp->funcs->enable_vblank)
> 119     {
> 120         comp->funcs->enable_vblank(comp->dev, vblank_cb, vblank_cb_data);
> 121 printk(KERN_ALERT "DEBUG: Passed %s %d \n",__FUNCTION__,__LINE__);
> 122     }
> 123 }
> 
> i see both messages, but mtk_crtc_ddp_irq is never called and so the other 2 not.

Yes, In my case the irq isr is also not called after resume which cause the warning
even though "enable_vblank" do get called. Don't know why is that.

> 
> root at bpi-r2:~# dmesg | grep -i DEBUG
> [    6.433509] DEBUG: Passed mtk_drm_crtc_enable_vblank 510
> [    6.433530] DEBUG: Passed mtk_ddp_comp_enable_vblank 117
> [    6.433537] DEBUG: Passed mtk_ddp_comp_enable_vblank 121 <<<
> 
> 
> comp->funcs->enable_vblank should be mtk_drm_crtc_enable_vblank, right?

No, this is a bit confusing , there are also the funcs of the components, see in file mtk_drm_ddp_comp.c
so for mt7623  it is mtk_ovl_enable_vblank.

Thanks,
Dafna

> 
> 641 static const struct drm_crtc_funcs mtk_crtc_funcs = {
> 642     .set_config     = drm_atomic_helper_set_config,
> 643     .page_flip      = drm_atomic_helper_page_flip,
> 644     .destroy        = mtk_drm_crtc_destroy,
> 645     .reset          = mtk_drm_crtc_reset,
> 646     .atomic_duplicate_state = mtk_drm_crtc_duplicate_state,
> 647     .atomic_destroy_state   = mtk_drm_crtc_destroy_state,
> 648     .enable_vblank      = mtk_drm_crtc_enable_vblank, <<<<<<<
> 649     .disable_vblank     = mtk_drm_crtc_disable_vblank,
> 650 };
> 
> but it looks like a recursion:
> mtk_drm_crtc_enable_vblank calls mtk_ddp_comp_enable_vblank => enable_vblank (=mtk_drm_crtc_enable_vblank), but i see the messages not repeating
> 
> mtk_drm_crtc_enable_vblank(struct drm_crtc *crtc)
> 511     mtk_ddp_comp_enable_vblank(comp, mtk_crtc_ddp_irq, &mtk_crtc->base);
> 
> 113 static inline void mtk_ddp_comp_enable_vblank(struct mtk_ddp_comp *comp,
> 114                           void (*vblank_cb)(void *),
> 115                           void *vblank_cb_data)
> 116 {
> 118     if (comp->funcs && comp->funcs->enable_vblank)
> 120         comp->funcs->enable_vblank(comp->dev, vblank_cb, vblank_cb_data);
> 
> but params do not match...comp->funcs->enable_vblank takes 3 arguments but comp->funcs->enable_vblank has only one.something i miss here...
> 
> i guess not, but is watchdog somehow involved? i ask because i see this on reboot/poweroff:
> 
> "watchdog: watchdog0: watchdog did not stop!"
> 
> i see this with my 5.13, 5.12-drm (5.12.0+mtk/core drm-patches) and 5.12.14 too (hdmi is working there), but not 5.12.0!
> that means something in drm-patches (mtk/core) breaks watchdog. maybe the recursion mentioned above?
> 
> regards Frank
> 
> 
>> Gesendet: Donnerstag, 08. Juli 2021 um 09:22 Uhr
>> Von: "Dafna Hirschfeld" <dafna.hirschfeld at collabora.com>
> 
>>
>> Hi Frank,
>>
>>
>> On 06.07.21 11:54, Frank Wunderlich wrote:
>>> Hi,
>>>
>>> i've noticed that HDMI is broken at least on my board (Bananapi-r2,mt7623) on 5.13.
>>>
>>> after some research i noticed that it is working till
>>>
>>> commit 2e477391522354e763aa62ee3e281c1ad9e8eb1b
>>> Author: Dafna Hirschfeld <dafna.hirschfeld at collabora.com>
> 
>>
>> We also encountered that warning on mt8173 device - Acer Chromebook R13. It happen after resuming from suspend to ram.
>> We could not find a version that works and we were not able to find the fix of the bug.
>> It seems like the irq isr is not called after resuming from suspend.
>> Please share if you have new findings regarding that bug.
>>
>> Thanks,
>> Dafna
>