LSPCON initialization still fails sometimes during system resume. The machine is an SKL-6770HQ, LSPCON is MegaChips with revisions HW-rev 2.1 SW-rev 1.29. The plan is to fix this by waiting with the intialization of the chip until it asserts HPD. [ 205.411044] [drm:lspcon_resume [i915]] LSPCON recovering in PCON mode after 356 ms [ 205.411530] [drm:drm_dp_i2c_do_msg] native defer [ 205.412726] [drm:drm_dp_i2c_do_msg] native defer [ 205.413961] [drm:drm_dp_i2c_do_msg] native defer [ 205.415168] [drm:drm_dp_i2c_do_msg] native defer [ 205.416398] [drm:drm_dp_i2c_do_msg] native defer [ 205.417594] [drm:drm_dp_i2c_do_msg] native defer [ 205.418797] [drm:drm_dp_i2c_do_msg] native defer [ 205.419504] [drm:drm_dp_i2c_do_msg] too many retries, giving up [ 205.420002] [drm:drm_dp_i2c_do_msg] native defer [ 205.421198] [drm:drm_dp_i2c_do_msg] native defer [ 205.422418] [drm:drm_dp_i2c_do_msg] native defer [ 205.423622] [drm:drm_dp_i2c_do_msg] native defer [ 205.424817] [drm:drm_dp_i2c_do_msg] native defer [ 205.426014] [drm:drm_dp_i2c_do_msg] native defer [ 205.427225] [drm:drm_dp_i2c_do_msg] native defer [ 205.427930] [drm:drm_dp_i2c_do_msg] too many retries, giving up [ 205.427937] [drm:drm_lspcon_get_mode] *ERROR* LSPCON read(0x80, 0x41) failed [ 205.428000] [drm:lspcon_wait_mode [i915]] *ERROR* Error reading LSPCON mode [ 205.428055] [drm:lspcon_wait_mode [i915]] Current LSPCON mode INVALID [ 205.428553] [drm:drm_dp_i2c_do_msg] native defer [ 205.429750] [drm:drm_dp_i2c_do_msg] native defer [ 205.430961] [drm:drm_dp_i2c_do_msg] native defer [ 205.432158] [drm:drm_dp_i2c_do_msg] native defer [ 205.433350] [drm:drm_dp_i2c_do_msg] native defer [ 205.434564] [drm:drm_dp_i2c_do_msg] native defer [ 205.435762] [drm:drm_dp_i2c_do_msg] native defer [ 205.436468] [drm:drm_dp_i2c_do_msg] too many retries, giving up [ 205.436967] [drm:drm_dp_i2c_do_msg] native defer [ 205.438159] [drm:drm_dp_i2c_do_msg] native defer [ 205.439399] [drm:drm_dp_i2c_do_msg] native defer [ 205.440594] [drm:drm_dp_i2c_do_msg] native defer [ 205.441797] [drm:drm_dp_i2c_do_msg] native defer [ 205.443005] [drm:drm_dp_i2c_do_msg] native defer [ 205.444202] [drm:drm_dp_i2c_do_msg] native defer [ 205.444930] [drm:drm_dp_i2c_do_msg] too many retries, giving up [ 205.444936] [drm:drm_lspcon_get_mode] *ERROR* LSPCON read(0x80, 0x41) failed [ 205.445013] [drm:lspcon_change_mode.constprop.4 [i915]] *ERROR* Error reading LSPCON mode [ 205.445062] [drm:lspcon_resume [i915]] *ERROR* LSPCON resume failed
An APL notebook with a MegaChips HW-rev 2.1 SW-rev 1.39 also fails sporadically in the same way, planning to use the same HPD fix as in the SKL case.
Reference to Imre's patchset: https://patchwork.freedesktop.org/series/18656/
The bug didn't trigger for a while now in CI, assuming fixed with the patchset in comment 2.
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