From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pankaj Chavan Subject: DP ports on Dell docking station can't drive 4k resolution Date: Fri, 29 Jan 2016 01:06:35 +0000 (UTC) Message-ID: <1060612444.1980627.1454029595121.JavaMail.yahoo@mail.yahoo.com> References: <1060612444.1980627.1454029595121.JavaMail.yahoo.ref@mail.yahoo.com> Reply-To: Pankaj Chavan Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============1014584273==" Return-path: Received: from nm11-vm1.bullet.mail.bf1.yahoo.com (nm11-vm1.bullet.mail.bf1.yahoo.com [98.139.213.152]) by gabe.freedesktop.org (Postfix) with ESMTPS id 3CB646E8E7 for ; Thu, 28 Jan 2016 17:06:37 -0800 (PST) List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" To: "intel-gfx@lists.freedesktop.org" List-Id: intel-gfx@lists.freedesktop.org --===============1014584273== Content-Type: multipart/alternative; boundary="----=_Part_1980626_803601938.1454029595118" ------=_Part_1980626_803601938.1454029595118 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Hi All, My work recently updated our laptops to a Dell Lattitude E7450 laptop and a= ccompanying Dell E-Port plus advanced docking station.=C2=A0 The machine ha= sBroadwell Core I7 processor and integrated graphics.=C2=A0 I've tried the = latest Ubuntu 15.10 (kernel version 4.2.0-25) with updated drivers=C2=A0 fr= om 01.org, and also running Linux Mint 17.3 based on the 14.4 Ubuntu LTS re= lease, which runs LInux kernel version 3.19.0-32. I have a 32" external 4k monitor connected to it through DP/miniDP cable. I= have checked that the monitor is set up to use DP 1.2 protocol. The problem is that when I connect the monitor through the dock using a DP = cable, the monitor can't do 4k resolution. It tops out at 2560x1440 at 60Hz= .=C2=A0 However, if I connect the monitor directly to the laptop (with or w= ithout the laptop being on the dock), it can drive the full 4k@60Hz. Moreov= er, the laptop is able to drive the full 4k resolution on the Windows 7 ope= rating system, so the issue is definitely some device driver related. Needl= ess to say, I do not use Windows at all. Note that I've tried using xrandr = on the command line, and also through the GUI widget that Ubuntu provides. When ever I connect/disconnect a monitor, I do get a bunch of warnings abou= t interrupt controller, and FIFO underruns. Jan 25 13:03:53 XXXX kernel: [=C2=A0 536.304816] [drm:gen8_irq_handler [i91= 5_bpo]] *ERROR* The master control interrupt lied (SDE)! ....Jan 25 11:41:27 XXXX kernel: [26659.784376] [drm:intel_cpu_fifo_underru= n_irq_handler [i915_bpo]] *ERROR* CPU pipe B FIFO underrun Any help in resolving this would be appreciated. Is there a pointer to an e= xisting bug report/mailing list email?=C2=A0 I am sure I'll soon get tired = of the two step process of plonking down the laptop on the dock, and then a= dditionally connecting the display cable to the monitor. Thanks in advance, Pankaj ------=_Part_1980626_803601938.1454029595118 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable

Hi All,

My work recently updated our laptops to a Dell Lattitude E7450 laptop and=20 accompanying Dell E-Port plus advanced docking station. The machine h= as

Broadwell Core I7 processor and integrated graphics. I've tried the latest=20 Ubuntu 15.10 (kernel version 4.2.0-25) with updated drivers from=20 01.org, and also running Linux Mint 17.3 based on the 14.4 Ubuntu LTS=20 release, which runs LInux kernel version 3.19.0-32.

I have a 32" external 4k monitor connected to it through DP/miniDP cable. I have checked that the monitor is set up to use DP 1.2 protocol.

The problem is that when I connect the monitor through the dock using a DP=20 cable, the monitor can't do 4k resolution. It tops out at 2560x1440 at=20 60Hz. However, if I connect the monitor directly to the laptop (with = or without the laptop being on the dock), it can drive the full 4k@60Hz.=20 Moreover, the laptop is able to drive the full 4k resolution on the=20 Windows 7 operating system, so the issue is definitely some device=20 driver related. Needless to say, I do not use Windows at all. Note that=20 I've tried using xrandr on the command line, and also through the GUI=20 widget that Ubuntu provides.

=

When ever I connect/disconnect a monitor, I do get a bunch of w= arnings about interrupt controller, and FIFO underruns.

Jan 25 13:03:53 XXXX kernel: [ = ; 536.304816] [drm:gen8_irq_handler [i915_bpo]] *ERROR* The master control = interrupt lied (SDE)!
....

Jan 25 11:41:27 XXXX kernel: [26659.784376]=20 [drm:intel_cpu_fifo_underrun_irq_handler [i915_bpo]] *ERROR* CPU pipe B=20 FIFO underrun

Any help in resolving this would be appreciated. Is there a poi= nter to an existing bug report/mailing list email? I am sure I'll soon get tired of the two step process of= =20 plonking down the laptop on the dock, and then additionally connecting=20 the display cable to the monitor.

Thanks in advance,

Pankaj

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