** Description changed: [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 5.13 or newer use new way to handle DPCD backlight, and do not + need to this to the 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] + [Where problems could occur] + The quirk is for a dedicate panel, and won't affect other platforms.
** Description changed: [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 5.13 or newer use new way to handle DPCD backlight, and do not - need to this to the quirk. + 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. ** Tags added: oem-priority originate-from-1933030 somerville -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux 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: In Progress 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
