** Changed in: linux (Ubuntu)
Assignee: (unassigned) => Herton R. Krzesinski (herton)
** Description changed:
+ SRU Justification
+
+ Impact
+ Unable to achieve some resolutions through display port because of
+ driver miscalculation, or sub-optimal number of links x data rate
+ chosen.
+
+ Fix
+ upstream commit cd9dde44f47501394b9f0715b6a36a92aa74c0d0
+
+ Testcase
+ Try attach something to display port using a resolution which should be
+ supported by the hardware but isn't by the driver, or enable relevant
+ debug and watch dmesg for sub-optimal links x data rate chosen (eg.:
+ http://permalink.gmane.org/gmane.comp.freedesktop.xorg.drivers.intel/6397)
+
+ ==========================================================================
+
Speaking with the intel driver developers they told me there was a
mistake on how the needed bandwidth was calculated resulting in higher
resolutions not being accepted because the driver though DisplayPort did
not have enough bandwidth for it.
Commit cd9dde44f47501394b9f0715b6a36a92aa74c0d0 from the linux kernel
should be backported to fix it (I have build a local package and i can
verify it fixes the problem)
http://git.kernel.org/?p=linux/kernel/git/stable/linux-
stable.git;a=commit;h=cd9dde44f47501394b9f0715b6a36a92aa74c0d0
ProblemType: Bug
DistroRelease: Ubuntu 11.10
Package: linux-image (not installed)
ProcVersionSignature: Ubuntu 3.0.0-13.22-generic 3.0.6
Uname: Linux 3.0.0-13-generic x86_64
AlsaVersion: Advanced Linux Sound Architecture Driver Version 1.0.24.
ApportVersion: 1.23-0ubuntu4
Architecture: amd64
ArecordDevices:
- **** List of CAPTURE Hardware Devices ****
- card 0: PCH [HDA Intel PCH], device 0: ALC665 Analog [ALC665 Analog]
- Subdevices: 1/1
- Subdevice #0: subdevice #0
+ **** List of CAPTURE Hardware Devices ****
+ card 0: PCH [HDA Intel PCH], device 0: ALC665 Analog [ALC665 Analog]
+ Subdevices: 1/1
+ Subdevice #0: subdevice #0
AudioDevicesInUse:
- USER PID ACCESS COMMAND
- /dev/snd/controlC0: tsdgeos 1974 F.... pulseaudio
+ USER PID ACCESS COMMAND
+ /dev/snd/controlC0: tsdgeos 1974 F.... pulseaudio
CRDA: Error: [Errno 2] El fitxer o directori no existeix
Card0.Amixer.info:
- Card hw:0 'PCH'/'HDA Intel PCH at 0xf1c00000 irq 52'
- Mixer name : 'Intel CougarPoint HDMI'
- Components : 'HDA:10ec0665,102804b6,00100003
HDA:80862805,80860101,00100000'
- Controls : 27
- Simple ctrls : 13
+ Card hw:0 'PCH'/'HDA Intel PCH at 0xf1c00000 irq 52'
+ Mixer name : 'Intel CougarPoint HDMI'
+ Components : 'HDA:10ec0665,102804b6,00100003
HDA:80862805,80860101,00100000'
+ Controls : 27
+ Simple ctrls : 13
Date: Sat Dec 3 15:11:01 2011
HibernationDevice: RESUME=UUID=07110fa9-417f-4300-b034-16a190a16dce
InstallationMedia: Kubuntu 11.10 "Oneiric Ocelot" - Release amd64 (20111012)
MachineType: Dell Inc. Dell System XPS L502X
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.0.0-13-generic
root=UUID=5a15ae34-5eea-4f4e-8b2a-3bfb20eb9f35 ro
crashkernel=384M-2G:64M,2G-:128M quiet splash vt.handoff=7
RelatedPackageVersions:
- linux-restricted-modules-3.0.0-13-generic N/A
- linux-backports-modules-3.0.0-13-generic N/A
- linux-firmware 1.60
+ linux-restricted-modules-3.0.0-13-generic N/A
+ linux-backports-modules-3.0.0-13-generic N/A
+ linux-firmware 1.60
SourcePackage: linux
StagingDrivers: mei
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 10/20/2011
dmi.bios.vendor: Dell Inc.
dmi.bios.version: A07
dmi.board.name: 0YR8NN
dmi.board.vendor: Dell Inc.
dmi.board.version: A00
dmi.chassis.type: 8
dmi.chassis.vendor: Dell Inc.
dmi.chassis.version: 0.1
dmi.modalias:
dmi:bvnDellInc.:bvrA07:bd10/20/2011:svnDellInc.:pnDellSystemXPSL502X:pvr:rvnDellInc.:rn0YR8NN:rvrA00:cvnDellInc.:ct8:cvr0.1:
dmi.product.name: Dell System XPS L502X
dmi.sys.vendor: Dell Inc.
** Also affects: linux (Ubuntu Oneiric)
Importance: Undecided
Status: New
** Changed in: linux (Ubuntu Oneiric)
Importance: Undecided => Medium
** Changed in: linux (Ubuntu Oneiric)
Assignee: (unassigned) => Herton R. Krzesinski (herton)
** Changed in: linux (Ubuntu)
Status: Triaged => Fix Released
** Changed in: linux (Ubuntu Oneiric)
Status: New => In Progress
** Patch added: "0001-drm-i915-dp-Fix-the-math-in-intel_dp_link_required.patch"
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/899598/+attachment/2621857/+files/0001-drm-i915-dp-Fix-the-math-in-intel_dp_link_required.patch
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https://bugs.launchpad.net/bugs/899598
Title:
[Patch] The resolution of Display Port for intel cards is limited
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