linux-dev/drivers/gpu/drm/drm_dp_helper.c, branch linus/master

drm/dp: Move DisplayPort helpers into separate helper module

2022-01-17T10:25:44Z

Move DisplayPort functions into a separate module to reduce the size of the KMS helpers. Select DRM_DP_HELPER for all users of the code. To avoid naming conflicts, rename drm_dp_helper.c to drm_dp.c This change can help to reduce the size of the kernel binary. Some numbers from a x86-64 test build: Before: drm_kms_helper.ko: 447480 bytes After: drm_dp_helper.ko: 216632 bytes drm_kms_helper.ko: 239424 bytes For early-boot graphics, generic DRM drivers, such as simpledrm, require DRM KMS helpers to be built into the kernel. Generic helper functions for DisplayPort take up a significant portion of DRM KMS helper library. These functions are not used by generic drivers and can be loaded as a module. v3: * fix include statement in DRM selftests v2: * move DP helper code into dp/ (Jani) Signed-off-by: Thomas Zimmermann Acked-by: Lyude Paul Acked-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20220114114535.29157-4-tzimmermann@suse.de

drm/dp: Move DP declarations into separate header file

2022-01-17T10:25:44Z

Split the DP declarations from other helpers before moving the DP functions into a separate module. v2: * forward-declare struct drm_dp_aux (Jani) * add include guards in drm_dp_helper_internal.h Signed-off-by: Thomas Zimmermann Acked-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20220114114535.29157-3-tzimmermann@suse.de

drm/dp, drm/i915: Add support for VESA backlights using PWM for brightness control

2021-11-17T22:36:48Z

Now that we've added support to i915 for controlling panel backlights that need PWM to be enabled/disabled, let's finalize this and add support for controlling brightness levels via PWM as well. This should hopefully put us towards the path of supporting _ALL_ backlights via VESA's DPCD interface which would allow us to finally start trusting the DPCD again. Note however that we still don't enable using this by default on i915 when it's not needed, primarily because I haven't yet had a chance to confirm if it's safe to do this on the one machine in Intel's CI that had an issue with this: samus-fi-bdw. I have done basic testing of this on other machines though, by manually patching i915 to force it into PWM-only mode on some of my laptops. v2: * Correct documentation (thanks Doug!) * Get rid of backlight caps Signed-off-by: Lyude Paul Reviewed-by: Doug Anderson Cc: Rajeev Nandan Cc: Satadru Pramanik Link: https://patchwork.freedesktop.org/patch/msgid/20211105183342.130810-5-lyude@redhat.com

drm/dp: Don't read back backlight mode in drm_edp_backlight_enable()

2021-11-17T22:36:48Z

As it turns out, apparently some machines will actually leave additional backlight functionality like dynamic backlight control on before the OS loads. Currently we don't take care to disable unsupported features when writing back the backlight mode, which can lead to some rather strange looking behavior when adjusting the backlight. So, let's fix this by just not reading back the current backlight mode on initial enable. I don't think there should really be any downsides to this, and this will ensure we don't leave any unsupported functionality enabled. This should fix at least one (but not all) of the issues seen with DPCD backlight support on fi-bdw-samus v5: * Just avoid reading back DPCD register - Doug Anderson Signed-off-by: Lyude Paul Fixes: 867cf9cd73c3 ("drm/dp: Extract i915's eDP backlight code into DRM helpers") Reviewed-by: Douglas Anderson Link: https://patchwork.freedesktop.org/patch/msgid/20211105183342.130810-4-lyude@redhat.com

Merge drm/drm-next into drm-misc-next

2021-10-25T13:27:56Z

drm-misc-next hasn't been updated in a while and I need a post -rc2 state to merge some vc4 patches. Signed-off-by: Maxime Ripard

drm/dp: reuse the 8b/10b link training delay helpers

2021-10-19T08:30:27Z

Reuse the 8b/10b link training delay helpers. Functionally this skips the check for invalid values for DPCD 1.4 and later at clock recovery delay (as it's a fixed delay and bypasses the rd_interval) but the same value will be checked and invalid values reported at channel equalization. Reviewed-by: Ville Syrjälä Signed-off-by: Jani Nikula Link: https://patchwork.freedesktop.org/patch/msgid/20211014150059.28957-2-jani.nikula@intel.com

drm/dp: add helpers to read link training delays

2021-10-19T08:29:51Z

The link training delays are different and/or available in different DPCD offsets depending on: - Clock recovery vs. channel equalization - DPRX vs. LTTPR - 128b/132b vs. 8b/10b - DPCD 1.4+ vs. earlier Add helpers to get the correct delays in us, reading DPCD if necessary. This is more straightforward than trying to retrofit the existing helpers to take 128b/132b into account. Having to pass in the DPCD receiver cap field seems unavoidable, because reading it involves checking the revision and reading extended receiver cap. So unfortunately the interface is mixed cached and read as needed. v2: Remove delay_us < 0 check and the whole local var (Ville) Cc: Ville Syrjälä Reviewed-by: Ville Syrjälä Signed-off-by: Jani Nikula Link: https://patchwork.freedesktop.org/patch/msgid/20211014150059.28957-1-jani.nikula@intel.com

drm/dp: add helper for extracting adjust 128b/132b TX FFE preset

2021-09-20T15:45:35Z

The DP 2.0 128b/132b channel coding uses TX FFE presets instead of vswing and pre-emphasis. Cc: dri-devel@lists.freedesktop.org Reviewed-by: Ville Syrjälä Acked-by: Maxime Ripard Signed-off-by: Jani Nikula Link: https://patchwork.freedesktop.org/patch/msgid/4ba129c51aeb01a5f210de7026abe704a554a178.1631191763.git.jani.nikula@intel.com

drm/dp: use more of the extended receiver cap

2021-09-20T15:44:43Z

Extend the use of extended receiver cap at 0x2200 to cover MAIN_LINK_CHANNEL_CODING_CAP in 0x2206, in case an implementation hides the DP 2.0 128b/132b channel encoding cap. v2: Extend to DP_RECEIVER_CAP_SIZE (Ville) Cc: Lyude Paul Cc: dri-devel@lists.freedesktop.org Cc: Manasi Navare Cc: Ville Syrjälä Reviewed-by: Lyude Paul Acked-by: Maxime Ripard Signed-off-by: Jani Nikula Link: https://patchwork.freedesktop.org/patch/msgid/649051cb896821147feee91aab1f2abc523c1353.1631191763.git.jani.nikula@intel.com

drm/dp: add DP 2.0 UHBR link rate and bw code conversions

2021-09-20T15:43:58Z

The bw code equals link_rate / 0.27 Gbps only for 8b/10b link rates. Handle DP 2.0 UHBR rates as special cases, though this is not pretty. Cc: dri-devel@lists.freedesktop.org Reviewed-by: Ville Syrjälä Acked-by: Maxime Ripard Signed-off-by: Jani Nikula Link: https://patchwork.freedesktop.org/patch/msgid/cab4edda8834d6b4db610fabb5e1f1f18ae33c2c.1631191763.git.jani.nikula@intel.com