| Message ID | 20151007153202.GN26517@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 10/7/15, Ville Syrjälä <ville.syrjala@linux.intel.com> wrote: > On Wed, Oct 07, 2015 at 10:29:22AM -0400, Nick Bowler wrote: >> On 10/7/15, Ville Syrjälä <ville.syrjala@linux.intel.com> wrote: >> > On Tue, Oct 06, 2015 at 11:42:33AM -0400, Nick Bowler wrote: >> >> On 9/24/15, Nick Bowler <nbowler@draconx.ca> wrote: >> >> > Testing out 4.3-rc2, first thing I notice is that the VGA output is >> >> > not working. Specifically, the display is continuously powering on >> >> > and off -- at no point is any image visible on the screen (I am >> >> > expecting to see the console output). The display connected to the >> >> > HDMI output is working fine. >> [...] > Hmm. You said VGA has the problem, but HDMI does not. Was the problem > happening even when you have both displays enabled at the same time, or > just when VGA was enabled alone? When I boot with HDMI cable disconnected, there is no change in behaviour for the VGA output. > I've attached two potential patches that might help. Can you give a try > to just patch 1, and if that alone doesn't help then both patches > together? I will try. Cheers, Nick
On 10/7/15, Nick Bowler <nbowler@draconx.ca> wrote: > On 10/7/15, Ville Syrjälä <ville.syrjala@linux.intel.com> wrote: >> On Wed, Oct 07, 2015 at 10:29:22AM -0400, Nick Bowler wrote: >>> On 10/7/15, Ville Syrjälä <ville.syrjala@linux.intel.com> wrote: >>> > On Tue, Oct 06, 2015 at 11:42:33AM -0400, Nick Bowler wrote: >>> >> On 9/24/15, Nick Bowler <nbowler@draconx.ca> wrote: >>> >> > Testing out 4.3-rc2, first thing I notice is that the VGA output is >>> >> > not working. Specifically, the display is continuously powering on >>> >> > and off -- at no point is any image visible on the screen (I am >>> >> > expecting to see the console output). The display connected to the >>> >> > HDMI output is working fine. >>> [...] >> Hmm. You said VGA has the problem, but HDMI does not. Was the problem >> happening even when you have both displays enabled at the same time, or >> just when VGA was enabled alone? > > When I boot with HDMI cable disconnected, there is no change in behaviour > for the VGA output. Clarification: normally both displays are connected. So the original issue is that only one of two displays are working.
On 10/7/15, Ville Syrjälä <ville.syrjala@linux.intel.com> wrote: > On Wed, Oct 07, 2015 at 10:29:22AM -0400, Nick Bowler wrote: >> On 10/7/15, Ville Syrjälä <ville.syrjala@linux.intel.com> wrote: >> > On Tue, Oct 06, 2015 at 11:42:33AM -0400, Nick Bowler wrote: >> >> On 9/24/15, Nick Bowler <nbowler@draconx.ca> wrote: >> >> > Testing out 4.3-rc2, first thing I notice is that the VGA output is >> >> > not working. Specifically, the display is continuously powering on >> >> > and off -- at no point is any image visible on the screen (I am >> >> > expecting to see the console output). The display connected to the >> >> > HDMI output is working fine. >> [...] > I've attached two potential patches that might help. Can you give a try > to just patch 1, and if that alone doesn't help then both patches > together? Patch #1: no change. Patch #1+#2: this works. Regards, Nick
On Wed, Oct 07, 2015 at 02:50:34PM -0400, Nick Bowler wrote: > On 10/7/15, Ville Syrjälä <ville.syrjala@linux.intel.com> wrote: > > On Wed, Oct 07, 2015 at 10:29:22AM -0400, Nick Bowler wrote: > >> On 10/7/15, Ville Syrjälä <ville.syrjala@linux.intel.com> wrote: > >> > On Tue, Oct 06, 2015 at 11:42:33AM -0400, Nick Bowler wrote: > >> >> On 9/24/15, Nick Bowler <nbowler@draconx.ca> wrote: > >> >> > Testing out 4.3-rc2, first thing I notice is that the VGA output is > >> >> > not working. Specifically, the display is continuously powering on > >> >> > and off -- at no point is any image visible on the screen (I am > >> >> > expecting to see the console output). The display connected to the > >> >> > HDMI output is working fine. > >> [...] > > I've attached two potential patches that might help. Can you give a try > > to just patch 1, and if that alone doesn't help then both patches > > together? > > Patch #1: no change. > Patch #1+#2: this works. Cool. I can see similar effects when manually frobbing the register on my 946GZ, except somehow it still manages to work without these patches. Not quite sure why that is. But anyway, I'll polish the patches a bit and send them out.
From 78ee4cbf2560891e59e6ae58fbcd197a34012819 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Ville=20Syrj=C3=A4l=C3=A4?= <ville.syrjala@linux.intel.com> Date: Wed, 7 Oct 2015 18:27:33 +0300 Subject: [PATCH 2/2] enable VGA mode before P1/P2 write --- drivers/gpu/drm/i915/intel_display.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c index f4fdff9..036550f 100644 --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -1743,6 +1743,12 @@ static void i9xx_enable_pll(struct intel_crtc *crtc) I915_READ(DPLL(!crtc->pipe)) | DPLL_DVO_2X_MODE); } + /* + * Apparently we need to have VGA mode enabled + * prior to writing P1/P2, otherwise they won't take. + */ + I915_WRITE(reg, 0); + I915_WRITE(reg, dpll); /* Wait for the clocks to stabilize. */ -- 2.4.9