On Tue, Dec 01, 2015 at 04:51:24AM +0000, Scot Doyle wrote:
> On Tue, 1 Dec 2015, Jonathan Gray wrote:
> > On Tue, Dec 01, 2015 at 01:32:24AM +0000, Scot Doyle wrote:
> > > from Todd Previte
> > > Enable 5.4Ghz (HBR2) link rate for Displayport 1.2-capable devices
> > > 06ea66b6bb445043dc25a9626254d5c130093199 in mainline Linux
> > > 
> > > refactored to only support the GPU's both capable of HBR2 and 
> > > currently supported by inteldrm: Broadwell and non-ULT Haswell
> > > 
> > > ok?
> > 
> > Could you describe what prompted you to look into this?  A certain
> > display wouldn't work otherwise?
> 
> Yes, an Ultra HD monitor was refreshing at 30Hz with -current, and now
> refreshes at 60.
> 
> > Note that the check was a bit different before the code was overhauled
> > again in later revisions.
> > 
> > if (((IS_HASWELL(dev) && !IS_HSW_ULX(dev)) ||
> >     INTEL_INFO(dev)->gen >= 8) &&
> >     intel_dp->dpcd[DP_DPCD_REV] >= 0x12)
> > 
> > ULX implies ULT but ULT doesn't imply ULX.
> 
> After reviewing [1] I mistook support for UHD@60Hz with support for HBR2. 
> Thanks for pointing this out, ULX seems better.
> 
> [1] 
> https://software.intel.com/en-us/articles/quick-reference-guide-to-intel-processor-graphics
> 
> > I don't see the need for calling your hbr2_capable function under
> > the "Training Pattern 3 support" section, why do that when
> > the original code had a "intel_dp->dpcd[DP_DPCD_REV] >= 0x12" test?
> 
> There was a report of dmesg clutter without the version check, when a
> pre-Haswell gpu attached to a large (HBR2?) monitor in commit 
> 7809a61176b385ebb3299ea43c58b1bb31ffb8c0.

How about the following collection of commits then

commit 06ea66b6bb445043dc25a9626254d5c130093199
Author: Todd Previte <[email protected]>
Date:   Mon Jan 20 10:19:39 2014 -0700

    drm/i915: Enable 5.4Ghz (HBR2) link rate for Displayport 1.2-capable devices

commit 9bbfd20abe5025adbb0ac75160bd2e41158a9e83
Author: Paulo Zanoni <[email protected]>
Date:   Tue Apr 29 11:00:22 2014 -0300

    drm/i915: don't try DP_LINK_BW_5_4 on HSW ULX

commit f8d8a672f9370278ae2c9752ad3021662dbc42fd
Author: Jani Nikula <[email protected]>
Date:   Fri Sep 5 16:19:18 2014 +0300

    drm/i915/dp: add missing \n in the TPS3 debug message

commit 7809a61176b385ebb3299ea43c58b1bb31ffb8c0
Author: Jani Nikula <[email protected]>
Date:   Wed Oct 29 11:03:26 2014 +0200

    drm/i915/dp: only use training pattern 3 on platforms that support it

Index: i915_pciids.h
===================================================================
RCS file: /cvs/src/sys/dev/pci/drm/i915_pciids.h,v
retrieving revision 1.1
diff -u -p -r1.1 i915_pciids.h
--- i915_pciids.h       23 Sep 2015 23:12:11 -0000      1.1
+++ i915_pciids.h       1 Dec 2015 05:33:06 -0000
@@ -192,8 +192,8 @@
        INTEL_VGA_DEVICE(0x0A06, info), /* ULT GT1 mobile */ \
        INTEL_VGA_DEVICE(0x0A16, info), /* ULT GT2 mobile */ \
        INTEL_VGA_DEVICE(0x0A26, info), /* ULT GT3 mobile */ \
-       INTEL_VGA_DEVICE(0x0A0E, info), /* ULT GT1 reserved */ \
-       INTEL_VGA_DEVICE(0x0A1E, info), /* ULT GT2 reserved */ \
+       INTEL_VGA_DEVICE(0x0A0E, info), /* ULX GT1 mobile */ \
+       INTEL_VGA_DEVICE(0x0A1E, info), /* ULX GT2 mobile */ \
        INTEL_VGA_DEVICE(0x0A2E, info), /* ULT GT3 reserved */ \
        INTEL_VGA_DEVICE(0x0D06, info), /* CRW GT1 mobile */ \
        INTEL_VGA_DEVICE(0x0D16, info), /* CRW GT2 mobile */ \
Index: i915/i915_drv.h
===================================================================
RCS file: /cvs/src/sys/dev/pci/drm/i915/i915_drv.h,v
retrieving revision 1.72
diff -u -p -r1.72 i915_drv.h
--- i915/i915_drv.h     1 Nov 2015 14:07:43 -0000       1.72
+++ i915/i915_drv.h     1 Dec 2015 05:32:13 -0000
@@ -1954,6 +1954,9 @@ struct drm_i915_file_private {
 #define IS_ULT(dev)            (IS_HSW_ULT(dev) || IS_BDW_ULT(dev))
 #define IS_HSW_GT3(dev)                (IS_HASWELL(dev) && \
                                 ((dev)->pdev->device & 0x00F0) == 0x0020)
+/* ULX machines are also considered ULT. */
+#define IS_HSW_ULX(dev)                ((dev)->pdev->device == 0x0A0E || \
+                                (dev)->pdev->device == 0x0A1E)
 #define IS_PRELIMINARY_HW(intel_info) ((intel_info)->is_preliminary)
 
 /*
Index: i915/intel_dp.c
===================================================================
RCS file: /cvs/src/sys/dev/pci/drm/i915/intel_dp.c,v
retrieving revision 1.26
diff -u -p -r1.26 intel_dp.c
--- i915/intel_dp.c     23 Sep 2015 23:12:12 -0000      1.26
+++ i915/intel_dp.c     1 Dec 2015 05:38:09 -0000
@@ -94,13 +94,19 @@ static int
 intel_dp_max_link_bw(struct intel_dp *intel_dp)
 {
        int max_link_bw = intel_dp->dpcd[DP_MAX_LINK_RATE];
+       struct drm_device *dev = intel_dp->attached_connector->base.dev;
 
        switch (max_link_bw) {
        case DP_LINK_BW_1_62:
        case DP_LINK_BW_2_7:
                break;
        case DP_LINK_BW_5_4: /* 1.2 capable displays may advertise higher bw */
-               max_link_bw = DP_LINK_BW_2_7;
+               if (((IS_HASWELL(dev) && !IS_HSW_ULX(dev)) ||
+                    INTEL_INFO(dev)->gen >= 8) &&
+                   intel_dp->dpcd[DP_DPCD_REV] >= 0x12)
+                       max_link_bw = DP_LINK_BW_5_4;
+               else
+                       max_link_bw = DP_LINK_BW_2_7;
                break;
        default:
                WARN(1, "invalid max DP link bw val %x, using 1.62Gbps\n",
@@ -847,9 +853,10 @@ intel_dp_compute_config(struct intel_enc
        struct intel_connector *intel_connector = intel_dp->attached_connector;
        int lane_count, clock;
        int max_lane_count = drm_dp_max_lane_count(intel_dp->dpcd);
-       int max_clock = intel_dp_max_link_bw(intel_dp) == DP_LINK_BW_2_7 ? 1 : 
0;
+       /* Conveniently, the link BW constants become indices with a shift...*/
+       int max_clock = intel_dp_max_link_bw(intel_dp) >> 3;
        int bpp, mode_rate;
-       static int bws[2] = { DP_LINK_BW_1_62, DP_LINK_BW_2_7 };
+       static int bws[] = { DP_LINK_BW_1_62, DP_LINK_BW_2_7, DP_LINK_BW_5_4 };
        int link_avail, link_clock;
 
        if (HAS_PCH_SPLIT(dev) && !HAS_DDI(dev) && port != PORT_A)
@@ -2673,10 +2680,15 @@ intel_dp_complete_link_train(struct inte
        bool channel_eq = false;
        int tries, cr_tries;
        uint32_t DP = intel_dp->DP;
+       uint32_t training_pattern = DP_TRAINING_PATTERN_2;
+
+       /* Training Pattern 3 for HBR2 ot 1.2 devices that support it*/
+       if (intel_dp->link_bw == DP_LINK_BW_5_4 || intel_dp->use_tps3)
+               training_pattern = DP_TRAINING_PATTERN_3;
 
        /* channel equalization */
        if (!intel_dp_set_link_train(intel_dp, &DP,
-                                    DP_TRAINING_PATTERN_2 |
+                                    training_pattern |
                                     DP_LINK_SCRAMBLING_DISABLE)) {
                DRM_ERROR("failed to start channel equalization\n");
                return;
@@ -2703,7 +2715,7 @@ intel_dp_complete_link_train(struct inte
                if (!drm_dp_clock_recovery_ok(link_status, 
intel_dp->lane_count)) {
                        intel_dp_start_link_train(intel_dp);
                        intel_dp_set_link_train(intel_dp, &DP,
-                                               DP_TRAINING_PATTERN_2 |
+                                               training_pattern |
                                                DP_LINK_SCRAMBLING_DISABLE);
                        cr_tries++;
                        continue;
@@ -2719,7 +2731,7 @@ intel_dp_complete_link_train(struct inte
                        intel_dp_link_down(intel_dp);
                        intel_dp_start_link_train(intel_dp);
                        intel_dp_set_link_train(intel_dp, &DP,
-                                               DP_TRAINING_PATTERN_2 |
+                                               training_pattern |
                                                DP_LINK_SCRAMBLING_DISABLE);
                        tries = 0;
                        cr_tries++;
@@ -2864,6 +2876,15 @@ intel_dp_get_dpcd(struct intel_dp *intel
                        DRM_DEBUG_KMS("Detected EDP PSR Panel.\n");
                }
        }
+
+       /* Training Pattern 3 support, both source and sink */
+       if (intel_dp->dpcd[DP_DPCD_REV] >= 0x12 &&
+           intel_dp->dpcd[DP_MAX_LANE_COUNT] & DP_TPS3_SUPPORTED &&
+           (IS_HASWELL(dev) || INTEL_INFO(dev)->gen >= 8)) {
+               intel_dp->use_tps3 = true;
+               DRM_DEBUG_KMS("Displayport TPS3 supported\n");
+       } else
+               intel_dp->use_tps3 = false;
 
        if (!(intel_dp->dpcd[DP_DOWNSTREAMPORT_PRESENT] &
              DP_DWN_STRM_PORT_PRESENT))
Index: i915/intel_drv.h
===================================================================
RCS file: /cvs/src/sys/dev/pci/drm/i915/intel_drv.h,v
retrieving revision 1.8
diff -u -p -r1.8 intel_drv.h
--- i915/intel_drv.h    23 Sep 2015 23:12:12 -0000      1.8
+++ i915/intel_drv.h    1 Dec 2015 05:31:47 -0000
@@ -497,6 +497,7 @@ struct intel_dp {
        struct delayed_work panel_vdd_work;
        bool want_panel_vdd;
        bool psr_setup_done;
+       bool use_tps3;
        struct intel_connector *attached_connector;
 };
 

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