From mboxrd@z Thu Jan 1 00:00:00 1970 From: Brian Vincent Subject: 4096x2160 monitor has EDID reporting 3840x2160 Date: Sat, 22 Sep 2018 16:29:22 -0500 Message-ID: Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============0576833509==" Return-path: Received: from mail-qt1-x834.google.com (mail-qt1-x834.google.com [IPv6:2607:f8b0:4864:20::834]) by gabe.freedesktop.org (Postfix) with ESMTPS id DDD8B8930E for ; Sat, 22 Sep 2018 21:29:34 +0000 (UTC) Received: by mail-qt1-x834.google.com with SMTP id k38-v6so5244934qtk.11 for ; Sat, 22 Sep 2018 14:29:34 -0700 (PDT) List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" To: dri-devel@lists.freedesktop.org List-Id: dri-devel@lists.freedesktop.org --===============0576833509== Content-Type: multipart/alternative; boundary="000000000000c2b40e05767c7356" --000000000000c2b40e05767c7356 Content-Type: text/plain; charset="UTF-8" I have a LG 31MU97-B monitor. My understanding is that EDID does not have a way to report itself as a 4096x2160 monitor, so it reports itself as a 3840x2160 monitor. The mode that it actually supports for it's native resolution that I've been using looks like this: xrandr --newmode "4096x2160_60" 556.730 4096 4104 4136 4176 2160 2208 2216 2222 +hsync +vsync I can use this mode with X and it works fine, but I've been unable to get it to work with KMS and Wayland, since it uses the EDID. EDID has CEA extensions that can support some 4096x2160 video modes, but I've tried them, and they don't work since they're not exactly the modeline that it needs. I've found these DMT modes in drm_edid.c that seems like they would probably work: /* 0x57 - 4096x2160@60Hz RB */ { DRM_MODE("4096x2160", DRM_MODE_TYPE_DRIVER, 556744, 4096, 4104, 4136, 4176, 0, 2160, 2208, 2216, 2222, 0, DRM_MODE_FLAG_PHSYNC | DRM_MODE_FLAG_NVSYNC) }, /* 0x58 - 4096x2160@59.94Hz RB */ { DRM_MODE("4096x2160", DRM_MODE_TYPE_DRIVER, 556188, 4096, 4104, 4136, 4176, 0, 2160, 2208, 2216, 2222, 0, DRM_MODE_FLAG_PHSYNC | DRM_MODE_FLAG_NVSYNC) }, But... even if I manage to get the code to infer modes on my monitor, it'll reject them since the horizontal resolution is 4096 which is higher than the 3840 that my monitor's EDID reports. If I wanted to fix this for everyone, what would the proper fix even look like? Should this be added as a quirk for this monitor to force add the modes? Thanks, Brian Vincent --000000000000c2b40e05767c7356 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable

I have a=C2=A0LG 31MU97-B monitor.=C2=A0 My understanding = is that EDID does not have a way to report itself as a 4096x2160 monitor, s= o it reports itself as a 3840x2160 monitor.=C2=A0 The mode that it actually= supports for it's native resolution that I've been using looks lik= e this:

xrandr --newmode "4096x2160_60" 5= 56.730=C2=A0 4096 4104 4136 4176=C2=A0 2160 2208 2216 2222 +hsync +vsync

I can use this mode with X and it works fine, = but I've been unable to get it to work with KMS and Wayland, since it u= ses the EDID.=C2=A0 EDID has CEA extensions that can support some=C2=A04096= x2160 video modes, but I've tried them, and they don't work since t= hey're not exactly the modeline that it needs.

I've found these DMT modes in drm_edid.c that seems like they would pr= obably work:

= /* 0x57 - 4096x2160@60Hz RB */

{ DRM_MODE("4096x2160", DRM_MODE_TYPE_DRIVER, 55674= 4, 4096, 4104,

=C2=A0 = =C2=A04136, 4176, 0, 2160, 2208, 2216, 2222, 0,

=C2=A0 =C2=A0DRM_MODE_FLAG_PHSYNC | DRM_MODE_FLAG_N= VSYNC) },

/* 0x58 - 4096x= 2160@59.94Hz RB */

{ DRM_= MODE("4096x2160", DRM_MODE_TYPE_DRIVER, 556188, 4096, 4104,

=

=C2=A0 =C2=A04136, 4176, 0, 2= 160, 2208, 2216, 2222, 0,

=C2=A0 =C2=A0DRM_MODE_FLAG_PHSYNC | DRM_MODE_FLAG_NVSYNC) },

<= div>

But... even if I manage to get the code to infer modes o= n my monitor, it'll reject them since the horizontal resolution is 4096= which is higher than the 3840 that my monitor's EDID reports.

If I wanted to fix this for everyone, what would the prope= r fix even look like?=C2=A0 Should this be added as a quirk for this monito= r to force add the modes?

Thanks,

Brian = Vincent

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