Re: 4.9.62: intermittent flicker after upgrade from 4.9.61

[Rainer Fiebig <jrf@mailbox.org>]

Maarten Lankhorst wrote:
> Op 20-11-17 om 09:51 schreef Rainer Fiebig:
>> Jani Nikula wrote:
>>> On Sun, 19 Nov 2017, Greg KH <gregkh@linuxfoundation.org> wrote:
>>>> On Sun, Nov 19, 2017 at 01:44:06PM +0100, Rainer Fiebig wrote:
>>>>> Greg KH wrote:
>>>>>> On Sun, Nov 19, 2017 at 12:56:26PM +0100, Rainer Fiebig wrote:
>>>>>>> Greg KH wrote:
>>>>>>>> On Sat, Nov 18, 2017 at 05:08:20PM +0100, Rainer Fiebig wrote:
>>>>>>>>> Greg KH wrote:
>>>>>>>>>> On Sat, Nov 18, 2017 at 01:47:32PM +0100, Rainer Fiebig wrote:
>>>>>>>>>>> Hi!
>>>>>>>>>>>
>>>>>>>>>>> Hopefully the right addressee.
>>>>>>>>>>>
>>>>>>>>>>> Encountered two bad backports which cause screen-flicker.
>>>>>>>>>>> dmesg shows:
>>>>>>>>>>>
>>>>>>>>>>> ...
>>>>>>>>>>> [drm:ironlake_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
>>>>>>>>>>> [drm:ironlake_irq_handler [i915]] *ERROR* PCH transcoder A FIFO underrun
>>>>>>>>>>> [drm:ironlake_irq_handler [i915]] *ERROR* CPU pipe B FIFO underrun
>>>>>>>>>>> [drm:ironlake_irq_handler [i915]] *ERROR* PCH transcoder B FIFO underrun
>>>>>>>>>>> ...
>>>>>>>>>>>
>>>>>>>>>>> CPU: Intel Core i3 (Clarkdale/Ironlake)
>>>>>>>>>>>
>>>>>>>>>>> The backports are:
>>>>>>>>>>>
>>>>>>>>>>> - diff --git a/drivers/gpu/drm/i915/intel_pm.c
>>>>>>>>>>> b/drivers/gpu/drm/i915/intel_pm.c
>>>>>>>>>>>     index 49de476..277a802 100644
>>>>>>>>>>> - diff --git a/drivers/gpu/drm/i915/intel_drv.h
>>>>>>>>>>> b/drivers/gpu/drm/i915/intel_drv.h
>>>>>>>>>>>     index a19ec06..3ce9ba3 100644
>>>>>>>>>>>
>>>>>>>>>>> After reversing them the flicker is gone, no more messages in dmesg. All
>>>>>>>>>>> else OK so far.
>>>>>>>>>> So which commit was the one that caused the problem?  I will be glad to
>>>>>>>>>> revert it.
>>>>>>>>>>
>>>>>>>>>> thanks,
>>>>>>>>>>
>>>>>>>>>> greg k-h
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>> I started by reverting the more complex one first ("index
>>>>>>>>> 49de476..277a802100644"). But the kernel wouldn't compile then.
>>>>>>>> What git commit id is that?  I don't see those ids in the 4.9-stable
>>>>>>>> tree.
>>>>>>>>
>>>>>>>>> So I also reverted "index a19ec06..3ce9ba3 100644". After that the
>>>>>>>>> kernel compiled just fine and the problems were gone (still are).
>>>>>>>> Same here, what git commit id was this?
>>>>>>>>
>>>>>>>> thanks,
>>>>>>>>
>>>>>>>> greg k-h
>>>>>>>>
>>>>>>> OK, no mistake. IIRC, I took the patches (and the IDs) from the
>>>>>>> changelog for patch-4.9.62. I've attached both, so you can check yourself.
>>>>>>>
>>>>>>> I've also applied a freshly downloaded patch-4.9.62 to a freshly
>>>>>>> expanded 4.9 and re-compiled. The flicker is there. I haven't yet
>>>>>>> reverted the two patches but I'm confident that after having done so the
>>>>>>> flicker will be gone. If not I'll let you know.
>>>>>>>
>>>>>>> As a good news: 4.14 is *not* affected. So to me it seems those two
>>>>>>> patches are part of sort of a package and can not be backported alone.
>>>>>>>
>>>>>>> So long!
>>>>>>> Rainer Fiebig
>>>>>>> diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
>>>>>>> index 49de476..277a802 100644
>>>>>>> --- a/drivers/gpu/drm/i915/intel_pm.c
>>>>>>> +++ b/drivers/gpu/drm/i915/intel_pm.c
>>>>>>> @@ -27,6 +27,7 @@
>>>>>>>  
>>>>>>>  #include <linux/cpufreq.h>
>>>>>>>  #include <drm/drm_plane_helper.h>
>>>>>>> +#include <drm/drm_atomic_helper.h>
>>>>>>>  #include "i915_drv.h"
>>>>>>>  #include "intel_drv.h"
>>>>>>>  #include "../../../platform/x86/intel_ips.h"
>>>>>>> @@ -2017,9 +2018,9 @@ static void ilk_compute_wm_level(const struct drm_i915_private *dev_priv,
>>>>>>>  				 const struct intel_crtc *intel_crtc,
>>>>>>>  				 int level,
>>>>>>>  				 struct intel_crtc_state *cstate,
>>>>>>> -				 struct intel_plane_state *pristate,
>>>>>>> -				 struct intel_plane_state *sprstate,
>>>>>>> -				 struct intel_plane_state *curstate,
>>>>>>> +				 const struct intel_plane_state *pristate,
>>>>>>> +				 const struct intel_plane_state *sprstate,
>>>>>>> +				 const struct intel_plane_state *curstate,
>>>>>>>  				 struct intel_wm_level *result)
>>>>>>>  {
>>>>>>>  	uint16_t pri_latency = dev_priv->wm.pri_latency[level];
>>>>>>> @@ -2341,28 +2342,24 @@ static int ilk_compute_pipe_wm(struct intel_crtc_state *cstate)
>>>>>>>  	struct intel_pipe_wm *pipe_wm;
>>>>>>>  	struct drm_device *dev = state->dev;
>>>>>>>  	const struct drm_i915_private *dev_priv = to_i915(dev);
>>>>>>> -	struct intel_plane *intel_plane;
>>>>>>> -	struct intel_plane_state *pristate = NULL;
>>>>>>> -	struct intel_plane_state *sprstate = NULL;
>>>>>>> -	struct intel_plane_state *curstate = NULL;
>>>>>>> +	struct drm_plane *plane;
>>>>>>> +	const struct drm_plane_state *plane_state;
>>>>>>> +	const struct intel_plane_state *pristate = NULL;
>>>>>>> +	const struct intel_plane_state *sprstate = NULL;
>>>>>>> +	const struct intel_plane_state *curstate = NULL;
>>>>>>>  	int level, max_level = ilk_wm_max_level(dev), usable_level;
>>>>>>>  	struct ilk_wm_maximums max;
>>>>>>>  
>>>>>>>  	pipe_wm = &cstate->wm.ilk.optimal;
>>>>>>>  
>>>>>>> -	for_each_intel_plane_on_crtc(dev, intel_crtc, intel_plane) {
>>>>>>> -		struct intel_plane_state *ps;
>>>>>>> +	drm_atomic_crtc_state_for_each_plane_state(plane, plane_state, &cstate->base) {
>>>>>>> +		const struct intel_plane_state *ps = to_intel_plane_state(plane_state);
>>>>>>>  
>>>>>>> -		ps = intel_atomic_get_existing_plane_state(state,
>>>>>>> -							   intel_plane);
>>>>>>> -		if (!ps)
>>>>>>> -			continue;
>>>>>>> -
>>>>>>> -		if (intel_plane->base.type == DRM_PLANE_TYPE_PRIMARY)
>>>>>>> +		if (plane->type == DRM_PLANE_TYPE_PRIMARY)
>>>>>>>  			pristate = ps;
>>>>>>> -		else if (intel_plane->base.type == DRM_PLANE_TYPE_OVERLAY)
>>>>>>> +		else if (plane->type == DRM_PLANE_TYPE_OVERLAY)
>>>>>>>  			sprstate = ps;
>>>>>>> -		else if (intel_plane->base.type == DRM_PLANE_TYPE_CURSOR)
>>>>>>> +		else if (plane->type == DRM_PLANE_TYPE_CURSOR)
>>>>>>>  			curstate = ps;
>>>>>>>  	}
>>>>>>>  
>>>>>>> @@ -2384,11 +2381,9 @@ static int ilk_compute_pipe_wm(struct intel_crtc_state *cstate)
>>>>>>>  	if (pipe_wm->sprites_scaled)
>>>>>>>  		usable_level = 0;
>>>>>>>  
>>>>>>> -	ilk_compute_wm_level(dev_priv, intel_crtc, 0, cstate,
>>>>>>> -			     pristate, sprstate, curstate, &pipe_wm->raw_wm[0]);
>>>>>>> -
>>>>>>>  	memset(&pipe_wm->wm, 0, sizeof(pipe_wm->wm));
>>>>>>> -	pipe_wm->wm[0] = pipe_wm->raw_wm[0];
>>>>>>> +	ilk_compute_wm_level(dev_priv, intel_crtc, 0, cstate,
>>>>>>> +			     pristate, sprstate, curstate, &pipe_wm->wm[0]);
>>>>>>>  
>>>>>>>  	if (IS_HASWELL(dev) || IS_BROADWELL(dev))
>>>>>>>  		pipe_wm->linetime = hsw_compute_linetime_wm(cstate);
>>>>>>> @@ -2398,8 +2393,8 @@ static int ilk_compute_pipe_wm(struct intel_crtc_state *cstate)
>>>>>>>  
>>>>>>>  	ilk_compute_wm_reg_maximums(dev, 1, &max);
>>>>>>>  
>>>>>>> -	for (level = 1; level <= max_level; level++) {
>>>>>>> -		struct intel_wm_level *wm = &pipe_wm->raw_wm[level];
>>>>>>> +	for (level = 1; level <= usable_level; level++) {
>>>>>>> +		struct intel_wm_level *wm = &pipe_wm->wm[level];
>>>>>>>  
>>>>>>>  		ilk_compute_wm_level(dev_priv, intel_crtc, level, cstate,
>>>>>>>  				     pristate, sprstate, curstate, wm);
>>>>>>> @@ -2409,13 +2404,10 @@ static int ilk_compute_pipe_wm(struct intel_crtc_state *cstate)
>>>>>>>  		 * register maximums since such watermarks are
>>>>>>>  		 * always invalid.
>>>>>>>  		 */
>>>>>>> -		if (level > usable_level)
>>>>>>> -			continue;
>>>>>>> -
>>>>>>> -		if (ilk_validate_wm_level(level, &max, wm))
>>>>>>> -			pipe_wm->wm[level] = *wm;
>>>>>>> -		else
>>>>>>> -			usable_level = level;
>>>>>>> +		if (!ilk_validate_wm_level(level, &max, wm)) {
>>>>>>> +			memset(wm, 0, sizeof(*wm));
>>>>>>> +			break;
>>>>>>> +		}
>>>>>>>  	}
>>>>>>>  
>>>>>>>  	return 0;
>>>>>>> diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
>>>>>>> index a19ec06..3ce9ba3 100644
>>>>>>> --- a/drivers/gpu/drm/i915/intel_drv.h
>>>>>>> +++ b/drivers/gpu/drm/i915/intel_drv.h
>>>>>>> @@ -457,7 +457,6 @@ struct intel_crtc_scaler_state {
>>>>>>>  
>>>>>>>  struct intel_pipe_wm {
>>>>>>>  	struct intel_wm_level wm[5];
>>>>>>> -	struct intel_wm_level raw_wm[5];
>>>>>>>  	uint32_t linetime;
>>>>>>>  	bool fbc_wm_enabled;
>>>>>>>  	bool pipe_enabled;
>>>>>> Ok, so this looks like commit 8777b927b92cf5b6c29f9f9d3c737addea9ac8a7
>>>>>> upstream which is commit 7de694782cbe7840f2c0de6f1e70f41fc1b8b6e8 in
>>>>>> 4.9.62.
>>>>>>
>>>>>> I've cc:ed the authors of that patch now.
>>>>>>
>>>>>> Maarten, any hints?  Should I revert this from 4.9-stable, or was there
>>>>>> a follow-on patch that resolved this issue in mainline?
>>>>>>
>>>>>> thanks,
>>>>>>
>>>>>> greg k-h
>>>>>>
>>>>> OK, after reverting the patches, the flicker *is* gone.
>>>> Thanks for confirming this.
>>>>
>>>>> BTW (for the future): Was it the right way to address
>>>>> stable@vger.kernel.org in this matter or would the bugreport at
>>>>> freedesktop.org have been enough? I'm a bit unsure about that.
>>>> I have no idea what the i915 developers want, but as far as I'm
>>>> concerned, sending this to stable@vger was fine with me, I have no
>>>> problem doing a bit of work in tracking down the specific patch before
>>>> bugging the developers involved.
>>> Well, this one we wanted to be backported, and so indicated with cc:
>>> stable, but apparently it went south anyway. :(
>>>
>>> Rainer, does v4.14 work for you? I.e. is the commit okay or not before
>>> the backport?
>>>
>>> Maarten?
>>>
>>> BR,
>>> Jani.
>>>
>>>
>> 4.14 is OK, no problems.
>>
>> So long!
>> Rainer Fiebig
> 
> What happens when you apply both other backported patches on top?
> 
> https://cgit.freedesktop.org/~mlankhorst/linux/log/?h=v4.9
> 

So I applied the 2 new patches on top of the orig. 4.9.62.

Better now but not yet completely OK:

...
[drm:ironlake_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
[drm:ironlake_irq_handler [i915]] *ERROR* PCH transcoder A FIFO underrun
...

No random flicker so far but flicker when I enter a character in an
x-terminal.

Seems your patches fixed only half of the pipes. ;)

So long!
Rainer Fiebig