On Sun, 19 Nov 2017, Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx> 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@xxxxxxxxxxxxxxx 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.
--
Jani Nikula, Intel Open Source Technology Center