<html> <head> <base href="https://bugs.freedesktop.org/"> </head> <body> <div> <a class="bz_bug_link bz_status_NEW " title="NEW - I7-8700 onboard HDMI port does not support 4K resolution" href="https://bugs.freedesktop.org/show_bug.cgi?id=112018#c2">Comment # 2</a> on <a class="bz_bug_link bz_status_NEW " title="NEW - I7-8700 onboard HDMI port does not support 4K resolution" href="https://bugs.freedesktop.org/show_bug.cgi?id=112018">bug 112018</a> from <a class="email" href="mailto:jian-hong@endlessm.com" title="jian-hong@endlessm.com">jian-hong@endlessm.com</a> <pre>Created <a href="attachment.cgi?id=145753" name="attach_145753" title="dmesg with removed type 1 HDMI's max TMDS clock upper bound">attachment 145753</a> <a href="attachment.cgi?id=145753&action=edit" title="dmesg with removed type 1 HDMI's max TMDS clock upper bound">[details]</a> dmesg with removed type 1 HDMI's max TMDS clock upper bound If I remove the type 1 HDMI clock's upper bound like the diff based on latest mainline kernel, than we can have 4K on this desktop: diff --git a/drivers/gpu/drm/drm_dp_dual_mode_helper.c b/drivers/gpu/drm/drm_dp_dual_mode_helper.c index 1c9ea9f7fdaf..da30f4cfb01e 100644 --- a/drivers/gpu/drm/drm_dp_dual_mode_helper.c +++ b/drivers/gpu/drm/drm_dp_dual_mode_helper.c @@ -277,12 +277,12 @@ int drm_dp_dual_mode_max_tmds_clock(enum drm_dp_dual_mode_type type, * Type 1 adaptors are limited to 165MHz * Type 2 adaptors can tells us their limit */ - if (type < DRM_DP_DUAL_MODE_TYPE2_DVI) + if (type < DRM_DP_DUAL_MODE_TYPE1_DVI) return 165000; ret = drm_dp_dual_mode_read(adapter, DP_DUAL_MODE_MAX_TMDS_CLOCK, &max_tmds_clock, sizeof(max_tmds_clock)); - if (ret || max_tmds_clock == 0x00 || max_tmds_clock == 0xff) { + if (ret || max_tmds_clock == 0x00) { DRM_DEBUG_KMS("Failed to query max TMDS clock\n"); return 165000; } The type 1 HDMI's max TMDS clock becomes 637500 kHz, which is higher than the expectation of 3840x2160. [ 3.951002] [drm:drm_dp_dual_mode_detect [drm_kms_helper]] DP dual mode HDMI ID: DP-HDMI ADAPTOR\004 (err 0) [ 3.951966] [drm:drm_dp_dual_mode_detect [drm_kms_helper]] DP dual mode adaptor ID: ff (err 0) [ 3.952970] [drm:intel_hdmi_set_edid [i915]] DP dual mode adaptor (type 1 HDMI) detected (max TMDS clock: 637500 kHz)</pre> </div> <hr> You are receiving this mail because: <ul> <li>You are on the CC list for the bug.</li> <li>You are the QA Contact for the bug.</li> <li>You are the assignee for the bug.</li> </ul> </body> </html>