Re: Flickering with Intel i7-5700 (HD 5600) and Samsung 156HL01-102 panel

Hi Albert,

thanks a lot for your help. Unfortunately the patches didn't help (I tried
the 8bit, I was still getting the flickering, so I ignored your 2nd piece
of advice and tried the 12bit just in case). They all show exactly the same
flickering :'-(

I'm attaching kern.log for a boot with the 8bit version.

I have a hard time reading the logs (I've been using Linux since 1994, but
never messed with display stuff), but if I grep for lines mentioning "bpp",
I see that the where Ubuntu kernel logged this:

[drm:connected_sink_compute_bpp] clamping display bpp (was 36) to EDID
reported max of 18

The same kernel with your 8bit fix logs this:

[drm:connected_sink_compute_bpp] clamping display bpp (was 36) to EDID
reported max of 24
[drm:intel_dp_compute_config] clamping bpp for eDP panel to BIOS-provided 18

So it looks like your patch took effect, but was overridden by some BIOS
setting? Any idea on how to stop this from happening?

Thanks,

Jordi.


2015-11-11 10:25 GMT+01:00 Albert Freeman <[email protected]>:

> On 11 November 2015 at 07:21, Jordi Salvat i Alabart
> <[email protected]> wrote:
> > Thanks! I'll try this as soon as I can (probably over the weekend) and
> > report back.
> >
> > Regards,
> >
> > Jordi
> >
> > El dia 10/11/2015 2:27 p. m., "Albert Freeman" <
> [email protected]>
> > va escriure:
> >
> >> On 10 November 2015 at 13:10, Albert Freeman <[email protected]
> >
> >> wrote:
> >> > On 8 November 2015 at 19:05, Jordi Salvat i Alabart
> >> > <[email protected]> wrote:
> >> >> Noone? Not even a hint on where I could ask for help?
> >> >>
> >> >> :'-(
> >> >>
> >> >>
> >> >>
> >> >> 2015-10-26 0:18 GMT+01:00 Jordi Salvat i Alabart
> >> >> <[email protected]>:
> >> >>>
> >> >>> Hi,
> >> >>>
> >> >>> My new MSI PE60 2QE laptop mounts an Intel i7-5700HQ, which carries
> >> >>> the
> >> >>> Integrated Graphics Chipset 5600, and a Samsung 156HL01-102 panel.
> >> >>>
> >> >>> The display works perfectly when I boot with the "nomodeset"
> parameter
> >> >>> in
> >> >>> the kernel command line -- but then I'm forced to use the
> framebuffer
> >> >>> driver, which doesn't allow multiple monitors.
> >> >>>
> >> >>> With KMS enabled (by removing the "nomodeset" parameter), X starts
> >> >>> correctly with the "intel" driver and I can use multiple monitors,
> but
> >> >>> the
> >> >>> laptop's panel shows an irregular flicker, ranging from occasional
> >> >>> flickering horizontal black lines (which are really annoying) to a
> >> >>> constant
> >> >>> flashing & flickering making the display all but unusable.
> >> >>>
> >> >>> The flickering and flashing is less noticeable, but still there, in
> >> >>> the
> >> >>> text-mode VTs, even if I never start X. So the problem has to be in
> >> >>> the
> >> >>> kernel or modules, not in the X drivers.
> >> >>>
> >> >>> External monitors connected to the DP or HDMI ports don't show any
> >> >>> flickering.
> >> >>>
> >> >>> Things I have tried (among many others I've discovered were
> >> >>> irrelevant):
> >> >>>
> >> >>> Setting a number different video modes using xrandr
> >> >>> Booting with Kernel 3.19.0.25 with i915.enable_IPS=0 as suggested
> >> >>> here:
> >> >>> Screen flickering on Ubuntu Gnome 14.04 - 4K resolution
> >> >>> Booting with i915.powersave=0
> >> >>> Booting with acpi_osi=Linux
> >> >>> Upgrading to Ubuntu Vivid Vervet (kernel 3.19.0 with a backported
> i915
> >> >>> module)
> >> >>> Upgrading to Ubuntu Willy Werewolf (kernel 4.2.0)
> >> >>>
> >> >>> None of these have helped.
> >> >>>
> >> >>> I'm attaching kern.log for a full boot sequence with drm.debug=0xf.
> >> >>>
> >> >>> What steps can you recommend to try to diagnose and solve this
> >> >>> problem?
> >> >>>
> >> >>> Thanks a lot for your help,
> >> >>>
> >> >>> Jordi
> >> >>>
> >> >>
> >> >>
> >> >> _______________________________________________
> >> >> mesa-users mailing list
> >> >> [email protected]
> >> >> http://lists.freedesktop.org/mailman/listinfo/mesa-users
> >> >>
> >> > Does this solve the issue (it solves a issue with your monitor) (it is
> >> > applied ontop of the latest linus kernel tree at time of writing):
> >> > diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
> >> > index 05bb731..44c9422 100644
> >> > --- a/drivers/gpu/drm/drm_edid.c
> >> > +++ b/drivers/gpu/drm/drm_edid.c
> >> > @@ -139,6 +139,9 @@ static struct edid_quirk {
> >> >
> >> >         /* Panel in Samsung NP700G7A-S01PL notebook reports 6bpc */
> >> >         { "SEC", 0xd033, EDID_QUIRK_FORCE_8BPC },
> >> > +
> >> > +       /* Panel in Samsung 156HL01-102 display (for notebook) reports
> >> > 6bpc instead of 8bpc */
> >> > +       { "SDC", 0x324c, EDID_QUIRK_FORCE_8BPC },
> >> >  };
> >> >
> >> >  /*
> >> >
> >> >
> >> >
> >> > !!!OR!!! Since the DRM is trying to force part of your monitor into 36
> >> > bit mode, maybe this:
> >> >
> >> >
> >> >
> >> > diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
> >> > index 05bb731..44c9422 100644
> >> > --- a/drivers/gpu/drm/drm_edid.c
> >> > +++ b/drivers/gpu/drm/drm_edid.c
> >> > @@ -139,6 +139,9 @@ static struct edid_quirk {
> >> >
> >> >         /* Panel in Samsung NP700G7A-S01PL notebook reports 6bpc */
> >> >         { "SEC", 0xd033, EDID_QUIRK_FORCE_8BPC },
> >> > +
> >> > +       /* Panel in Samsung 156HL01-102 display (for notebook) reports
> >> > 6bpc instead of 12bpc */
> >> > +       { "SDC", 0x324c, EDID_QUIRK_FORCE_12BPC },
> >> >  };
> >> >
> >> >  /*
> >> Sorry those patches don't apply properly, here are ones that do
> After looking at intel drm driver code more carefully, don't use the
> 12 bpc one (12 * 3 == 36). The intel drm driver seems to first
> generate certain values based on your gpu model. It then reduces it
> based on display stuff (i.e. when I made the 12bpc version of the
> patch I was looking at the intial value based on gpu model). I don't
> think your display is capable of 36 bit color (12bpc) as the internet
> says it only has 95% sRGB (e.g. high end consumer monitor, but not
> perfect). 36bit is only for photographers and people producing
> movies/game textures/game environments and other special high end
> environments. Movies and games and practically every picture on the
> internet is sRGB which is fully supported by 8 bit stuff. So cd to the
> kernel source directory and execute git apply 8bit (with the 8bit
> "patch in the same folder)
>

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