> On Aug 17, 2020, at 00:22, Runyan, Arthur J <arthur.j.runyan@xxxxxxxxx> wrote: > > You'll need to read out the DDI_BUF_TRANS_* and DISPIO_CR_TX_BMU_CR0 registers at boot before i915 programs them and compare with what driver programs. > Rodrigo can probably show you how. Right, I'll wait for a patch then :) Kai-Heng > > -----Original Message----- > From: Kai-Heng Feng <kai.heng.feng@xxxxxxxxxxxxx> > Sent: Thursday, August 13, 2020 10:14 PM > To: Runyan, Arthur J <arthur.j.runyan@xxxxxxxxx> > Cc: Vivi, Rodrigo <rodrigo.vivi@xxxxxxxxx>; Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>; intel-gfx <intel-gfx@xxxxxxxxxxxxxxxxxxxxx> > Subject: Re: [Regression] "drm/i915: Implement display w/a #1143" breaks HDMI on ASUS GL552VW > > Hi, > >> On Aug 14, 2020, at 01:56, Runyan, Arthur J <arthur.j.runyan@xxxxxxxxx> wrote: >> >> The workaround is freeing up stuck vswing values to let new vswing programming kick in. Maybe the new vswing values are wrong. >> Try checking the vswing that driver programs against what BIOS/GOP programs. > > Do you mean to print out value of I915_READ()? > val = I915_READ(CHICKEN_TRANS(transcoder)); > > Kai-Heng > >> >> -----Original Message----- >> From: Vivi, Rodrigo <rodrigo.vivi@xxxxxxxxx> >> Sent: Thursday, August 13, 2020 9:50 AM >> To: Kai-Heng Feng <kai.heng.feng@xxxxxxxxxxxxx>; Runyan, Arthur J >> <arthur.j.runyan@xxxxxxxxx> >> Cc: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>; intel-gfx >> <intel-gfx@xxxxxxxxxxxxxxxxxxxxx> >> Subject: Re: [Regression] "drm/i915: Implement display w/a #1143" >> breaks HDMI on ASUS GL552VW >> >> Art, any comment here? >> >> I just checked and the W/a 1143 is implemented as described, but it is failing HDMI on this hybrid system. >> >>> On Aug 12, 2020, at 9:07 PM, Kai-Heng Feng <kai.heng.feng@xxxxxxxxxxxxx> wrote: >>> >>> Hi, >>> >>> There's a regression reported that HDMI output stops working after os upgrade: >>> https://bugs.launchpad.net/bugs/1871721 >>> >>> Here's the bisect result: >>> 0519c102f5285476d7868a387bdb6c58385e4074 is the first bad commit >>> commit 0519c102f5285476d7868a387bdb6c58385e4074 >>> Author: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> >>> Date: Mon Jan 22 19:41:31 2018 +0200 >>> >>> drm/i915: Implement display w/a #1143 >>> >>> Apparently SKL/KBL/CFL need some manual help to get the >>> programmed HDMI vswing to stick. Implement the relevant >>> workaround (display w/a #1143). >>> >>> Note that the relevant chicken bits live in a transcoder register >>> even though the bits affect a specific DDI port rather than a >>> specific transcoder. Hence we must pick the correct transcoder >>> register instance based on the port rather than based on the >>> cpu_transcoder. >>> >>> Also note that for completeness I included support for DDI A/E >>> in the code even though we never have HDMI on those ports. >>> >>> v2: CFL needs the w/a as well (Rodrigo and Art) >>> >>> Cc: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx> >>> Cc: Art Runyan <arthur.j.runyan@xxxxxxxxx> >>> Signed-off-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> >>> Link: https://patchwork.freedesktop.org/patch/msgid/20180122174131.28046-1-ville.syrjala@xxxxxxxxxxxxxxx >>> Reviewed-by: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx> >>> >>> >>> dmesg from drm-tip with drm.debug=0xe can be found here: >>> https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1871721/comments >>> / >>> 64 >>> >>> Kai-Heng >> >> > _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
