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

[Frank Wunderlich]

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.

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?

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