Re: [Intel-gfx] [PATCH] drm/i915/dp: DP PHY compliance for JSL

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On Thu, Jun 04, 2020 at 08:01:03PM +0000, Almahallawy, Khaled wrote:
> On Thu, 2020-06-04 at 22:06 +0300, Ville Syrjälä wrote:
> > On Thu, Jun 04, 2020 at 10:33:48AM +0530, Vidya Srinivas wrote:
> > > Signed-off-by: Khaled Almahallawy <khaled.almahallawy@xxxxxxxxx>
> > > Signed-off-by: Vidya Srinivas <vidya.srinivas@xxxxxxxxx>
> > > ---
> > >  drivers/gpu/drm/i915/display/intel_dp.c | 40
> > > ++++++++++++++++++++++++++-------
> > >  1 file changed, 32 insertions(+), 8 deletions(-)
> > > 
> > > diff --git a/drivers/gpu/drm/i915/display/intel_dp.c
> > > b/drivers/gpu/drm/i915/display/intel_dp.c
> > > index 7223367171d1..44663e8ac9a1 100644
> > > --- a/drivers/gpu/drm/i915/display/intel_dp.c
> > > +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> > > @@ -5470,22 +5470,32 @@ intel_dp_autotest_phy_ddi_disable(struct
> > > intel_dp *intel_dp)
> > >  	struct drm_i915_private *dev_priv = to_i915(dev);
> > >  	struct intel_crtc *crtc = to_intel_crtc(intel_dig_port-
> > > >base.base.crtc);
> > >  	enum pipe pipe = crtc->pipe;
> > > -	u32 trans_ddi_func_ctl_value, trans_conf_value,
> > > dp_tp_ctl_value;
> > > +	u32 trans_ddi_func_ctl_value, trans_conf_value,
> > > dp_tp_ctl_value, trans_ddi_port_mask;
> > > +	enum port port = intel_dig_port->base.port;
> > > +	i915_reg_t dp_tp_reg;
> > > +
> > > +	if (IS_ELKHARTLAKE(dev_priv)) {
> > > +		dp_tp_reg = DP_TP_CTL(port);
> > > +		trans_ddi_port_mask = TRANS_DDI_PORT_MASK;
> > > +	} else if (IS_TIGERLAKE(dev_priv)) {
> > > +		dp_tp_reg = TGL_DP_TP_CTL(pipe);
> > > +		trans_ddi_port_mask = TGL_TRANS_DDI_PORT_MASK;
> > > +	}
> > >  
> > >  	trans_ddi_func_ctl_value = intel_de_read(dev_priv,
> > >  						 TRANS_DDI_FUNC_CTL(pip
> > > e));
> > >  	trans_conf_value = intel_de_read(dev_priv, PIPECONF(pipe));
> > > -	dp_tp_ctl_value = intel_de_read(dev_priv, TGL_DP_TP_CTL(pipe));
> > >  
> > > +	dp_tp_ctl_value = intel_de_read(dev_priv, dp_tp_reg);
> > >  	trans_ddi_func_ctl_value &= ~(TRANS_DDI_FUNC_ENABLE |
> > > -				      TGL_TRANS_DDI_PORT_MASK);
> > > +					trans_ddi_port_mask);
> > >  	trans_conf_value &= ~PIPECONF_ENABLE;
> > >  	dp_tp_ctl_value &= ~DP_TP_CTL_ENABLE;
> > >  
> > >  	intel_de_write(dev_priv, PIPECONF(pipe), trans_conf_value);
> > >  	intel_de_write(dev_priv, TRANS_DDI_FUNC_CTL(pipe),
> > >  		       trans_ddi_func_ctl_value);
> > > -	intel_de_write(dev_priv, TGL_DP_TP_CTL(pipe), dp_tp_ctl_value);
> > > +	intel_de_write(dev_priv, dp_tp_reg, dp_tp_ctl_value);
> > 
> > All this ad-hoc modeset code really should not exist. It's going to
> > have different bugs than the norma modeset paths, so compliance
> > testing
> > this special code proves absolutely nothing about the normal modeset
> > code. IMO someone needs to take up the task of rewrtiting all this to
> > just perform normal modesets.

But isnt that behaviour of the scope against the compliance spec?
The PHY request as per the VESA compliance spec should only come through
a short pulse.
Yes if it comes through a long pulse, it will reset the link and this whole
code will fall apart.

Manasi

> 
> Agree. I've just found that we get kernel NULL pointer dereference and
> panic when we try to access to_intel_crtc(intel_dig_port-
> >base.base.crtc). This is because we didn't realize when we developed
> the code that test scope has an option to send PHY test request on Long
> HPD. Current desing assume PHY test request on short HPD. Because of
> that we got the following error
> 
> 
> [  106.810882] i915 0000:00:02.0: [drm:intel_hpd_irq_handler [i915]]
> digital hpd on [ENCODER:308:DDI F] - long
> [  106.810916] i915 0000:00:02.0: [drm:intel_hpd_irq_handler [i915]]
> Received HPD interrupt on PIN 9 - cnt: 10
> [  106.811026] i915 0000:00:02.0: [drm:intel_dp_hpd_pulse [i915]] got
> hpd irq on [ENCODER:308:DDI F] - long
> [  106.811095] i915 0000:00:02.0: [drm:i915_hotplug_work_func [i915]]
> running encoder hotplug functions
> [  106.811184] i915 0000:00:02.0: [drm:i915_hotplug_work_func [i915]]
> Connector DP-3 (pin 9) received hotplug event. (retry 0)
> [  106.811227] i915 0000:00:02.0: [drm:intel_dp_detect [i915]]
> [CONNECTOR:309:DP-3]
> [  106.811292] i915 0000:00:02.0: [drm:intel_power_well_enable [i915]]
> enabling TC cold off
> [  106.811365] i915 0000:00:02.0: [drm:tgl_tc_cold_request [i915]] TC
> cold block succeeded
> [  106.811489] i915 0000:00:02.0: [drm:__intel_tc_port_lock [i915]]
> Port F/TC#3: TC port mode reset (tbt-alt -> dp-alt)
> [  106.811663] i915 0000:00:02.0: [drm:intel_power_well_enable [i915]]
> enabling AUX F TC3
> [  106.812449] [drm:drm_dp_dpcd_read] AUX F/port F: 0x00000 AUX ->
> (ret= 15) 12 14 04 80 00 00 01 00 00 00 00 00 00 00 00
> [  106.812484] i915 0000:00:02.0: [drm:intel_dp_read_dpcd [i915]] DPCD:
> 12 14 04 80 00 00 01 00 00 00 00 00 00 00 00
> [  106.813266] [drm:drm_dp_dpcd_read] AUX F/port F: 0x00400 AUX ->
> (ret= 12) 00 00 00 00 00 00 00 00 00 00 00 00
> [  106.813271] [drm:drm_dp_read_desc] DP sink: OUI 00-00-00 dev-ID  HW-
> rev 0.0 SW-rev 0.0 quirks 0x0000
> [  106.813891] [drm:drm_dp_dpcd_read] AUX F/port F: 0x00200 AUX ->
> (ret=  1) 01
> [  106.813940] i915 0000:00:02.0: [drm:intel_dp_print_rates [i915]]
> source rates: 162000, 216000, 270000, 324000, 432000, 540000, 648000,
> 810000
> [  106.813974] i915 0000:00:02.0: [drm:intel_dp_print_rates [i915]]
> sink rates: 162000, 270000, 540000
> [  106.814007] i915 0000:00:02.0: [drm:intel_dp_print_rates [i915]]
> common rates: 162000, 270000, 540000
> [  106.814550] [drm:drm_dp_dpcd_read] AUX F/port F: 0x00021 AUX ->
> (ret=  1) 00
> [  106.814583] i915 0000:00:02.0: [drm:intel_dp_detect [i915]]
> [ENCODER:308:DDI F] MST support: port: yes, sink: no, modparam: yes
> 
> .....
> 
> [  106.927291] i915 0000:00:02.0: [drm:intel_dp_check_service_irq
> [i915]] PHY_PATTERN test requested
> [  106.927897] [drm:drm_dp_dpcd_read] AUX F/port F: 0x00219 AUX ->
> (ret=  1) 0a
> [  106.928507] [drm:drm_dp_dpcd_read] AUX F/port F: 0x00220 AUX ->
> (ret=  1) 04
> [  106.929143] [drm:drm_dp_dpcd_read] AUX F/port F: 0x00248 AUX ->
> (ret=  1) 00
> [  106.929824] [drm:drm_dp_dpcd_read] AUX F/port F: 0x00202 AUX ->
> (ret=  6) 00 00 80 00 00 00
> [  106.929830] BUG: kernel NULL pointer dereference, address:
> 0000000000000578
> [  106.936809] #PF: supervisor read access in kernel mode
> [  106.941953] #PF: error_code(0x0000) - not-present page
> [  106.947082] PGD 0 P4D 0 
> [  106.949643] Oops: 0000 [#1] PREEMPT SMP NOPTI
> [  106.954010] CPU: 6 PID: 200 Comm: kworker/6:2 Not tainted 5.7.0-rc7-
> CI-CI_DRM_8566+ #5
> [  106.975251] Workqueue: events i915_hotplug_work_func [i915]
> [  106.980887] RIP: 0010:intel_dp_process_phy_request+0x94/0x5a0 [i915]
> [  106.987239] Code: 48 83 c4 20 5b 5d 41 5c 41 5d 41 5e 41 5f c3 48 8d
> 74 24 12 4c 89 f7 e8 3a 3e 00 00 49 8b 86 28 ff ff ff 49 8b 9e d8 fe ff
> ff <48> 63 80 78 05 00 00 8b 93 54 0d 00 00 48 8d ab e8 0e 00 00 48 89
> [  107.005890] RSP: 0018:ffffc9000046fb20 EFLAGS: 00010246
> 
> I plan to temporarily fix this issue by ignoreing scope request on long
> HPD, until we have modeset based implementation.
> 
> > >  }
> > >  
> > >  static void
> > > @@ -5497,20 +5507,28 @@ intel_dp_autotest_phy_ddi_enable(struct
> > > intel_dp *intel_dp, uint8_t lane_cnt)
> > >  	enum port port = intel_dig_port->base.port;
> > >  	struct intel_crtc *crtc = to_intel_crtc(intel_dig_port-
> > > >base.base.crtc);
> > >  	enum pipe pipe = crtc->pipe;
> > > -	u32 trans_ddi_func_ctl_value, trans_conf_value,
> > > dp_tp_ctl_value;
> > > +	u32 trans_ddi_func_ctl_value, trans_conf_value,
> > > dp_tp_ctl_value, trans_ddi_sel_port;
> > > +	i915_reg_t dp_tp_reg;
> > > +
> > > +	if (IS_ELKHARTLAKE(dev_priv)) {
> > > +		dp_tp_reg = DP_TP_CTL(port);
> > > +		trans_ddi_sel_port = TRANS_DDI_SELECT_PORT(port);
> > > +	} else if (IS_TIGERLAKE(dev_priv)) {
> > > +		dp_tp_reg = TGL_DP_TP_CTL(pipe);
> > > +		trans_ddi_sel_port = TGL_TRANS_DDI_SELECT_PORT(port);
> > > +	}
> > >  
> > >  	trans_ddi_func_ctl_value = intel_de_read(dev_priv,
> > >  						 TRANS_DDI_FUNC_CTL(pip
> > > e));
> > >  	trans_conf_value = intel_de_read(dev_priv, PIPECONF(pipe));
> > >  	dp_tp_ctl_value = intel_de_read(dev_priv, TGL_DP_TP_CTL(pipe));
> > > -
> > >  	trans_ddi_func_ctl_value |= TRANS_DDI_FUNC_ENABLE |
> > > -				    TGL_TRANS_DDI_SELECT_PORT(port);
> > > +				    trans_ddi_sel_port;
> > >  	trans_conf_value |= PIPECONF_ENABLE;
> > >  	dp_tp_ctl_value |= DP_TP_CTL_ENABLE;
> > >  
> > >  	intel_de_write(dev_priv, PIPECONF(pipe), trans_conf_value);
> > > -	intel_de_write(dev_priv, TGL_DP_TP_CTL(pipe), dp_tp_ctl_value);
> > > +	intel_de_write(dev_priv, dp_tp_reg, dp_tp_ctl_value);
> > >  	intel_de_write(dev_priv, TRANS_DDI_FUNC_CTL(pipe),
> > >  		       trans_ddi_func_ctl_value);
> > >  }
> > > @@ -5557,6 +5575,7 @@ static u8
> > > intel_dp_autotest_phy_pattern(struct intel_dp *intel_dp)
> > >  static void intel_dp_handle_test_request(struct intel_dp
> > > *intel_dp)
> > >  {
> > >  	struct drm_i915_private *i915 = dp_to_i915(intel_dp);
> > > +	struct drm_i915_private *dev_priv = i915;
> > >  	u8 response = DP_TEST_NAK;
> > >  	u8 request = 0;
> > >  	int status;
> > > @@ -5582,6 +5601,11 @@ static void
> > > intel_dp_handle_test_request(struct intel_dp *intel_dp)
> > >  		response = intel_dp_autotest_edid(intel_dp);
> > >  		break;
> > >  	case DP_TEST_LINK_PHY_TEST_PATTERN:
> > > +		if (!IS_ELKHARTLAKE(dev_priv) ||
> > > !IS_TIGERLAKE(dev_priv)) {
> > > +			drm_dbg_kms(&i915->drm,
> > > +				"PHY compliance for platform not
> > > supported\n");
> > > +			return;
> > > +		}
> > >  		drm_dbg_kms(&i915->drm, "PHY_PATTERN test
> > > requested\n");
> > >  		response = intel_dp_autotest_phy_pattern(intel_dp);
> > >  		break;
> > > -- 
> > > 2.7.4
> > > 
> > > _______________________________________________
> > > Intel-gfx mailing list
> > > Intel-gfx@xxxxxxxxxxxxxxxxxxxxx
> > > https://lists.freedesktop.org/mailman/listinfo/intel-gfx
> > 
> > 
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@xxxxxxxxxxxxxxxxxxxxx
> https://lists.freedesktop.org/mailman/listinfo/intel-gfx
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