This bug is awaiting verification that the kernel in -proposed solves the problem. Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification-needed- focal' to 'verification-done-focal'. If the problem still exists, change the tag 'verification-needed-focal' to 'verification-failed-focal'.
If verification is not done by 5 working days from today, this fix will be dropped from the source code, and this bug will be closed. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you! ** Tags added: verification-needed-focal -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux-oem-5.10 in Ubuntu. https://bugs.launchpad.net/bugs/1933566 Title: XPS 9510 (TGL) Screen Brightness could not be changed Status in HWE Next: New Status in linux package in Ubuntu: Invalid Status in linux-oem-5.10 package in Ubuntu: Invalid Status in linux source package in Focal: In Progress Status in linux-oem-5.10 source package in Focal: Fix Committed Status in linux source package in Groovy: In Progress Status in linux source package in Hirsute: In Progress Bug description: [Impact] Dell XPS 15 9510(TGL) uses DPCD to control backlight, and need to add this panel to edid_quirk. kernel: [ 1.719773] i915 0000:00:02.0: [drm] Panel advertises DPCD backlight support, but VBT disagrees. If your backlight controls don't work try booting with i915.enable_dpcd_backlight=1. If your machine needs this, please file a _new_ bug report on drm/i915, see https://gitlab.freedesktop.org/drm/intel/-/wikis/How-to-file-i915-bugs for details. Kernel 5.12+ support the backlight via: commit: <4a8d79901d5b> ("drm/i915/dp: Enable Intel's HDR backlight interface (only SDR for now)"), and doesn't need this quirk. [Fix] Adding the panel's MFG to edid_quirk makes system switch to use DPCD to control backlight. [Test] Verified on Dell XPS 9510(TGL) [Where problems could occur] The quirk is for a dedicate panel, and won't affect other platforms. To manage notifications about this bug go to: https://bugs.launchpad.net/hwe-next/+bug/1933566/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
