| Message ID | 87txi8d7z4.fsf@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hi Jani, At Thu, 29 Aug 2013 14:58:23 +0300, Jani Nikula wrote: > > > Hi Takashi - > > On Thu, 29 Aug 2013, Takashi Iwai <tiwai@suse.de> wrote: > > a new laptop model we've been struggling has some strange hardware > > configuration. BIOS turns off backlight and skips its initialization > > when the machine is booted with the lid closed. This leaves > > BLC_PWM_PCH_CTL2 and other registers uninitialized. Because a proper > > max brightness value can't be obtained from this register, i915 driver > > doesn't create the own backlight control any more. It results in the > > permanent blank screen even after the lid is opened. > > > > Actually, the only missing piece is the initial BLC_PWM_PCH_CTL2 > > value. If I overwrite it via intel_reg_write before loading i915 > > module, everything works fine. > > > > Now I wonder whether we can get this max brightness value from > > somewhere else. Is it defined in VBT or anywhere else persistent? > > Please run tools/intel_bios_reader from intel-gpu-tools, and post the > results. If that fails, please attach hexdump of > /sys/kernel/debug/dri/0/i915_opregion. The PWM value should be in the > VBT, and we could use that as a fallback. If the value makes sense, that > is. Attached below. The tarball contains the boot cases where the lid is opened and closed. The output of intel_bios_dumper couldn't be read when the lid is closed, as it seems. In anyway, I see no obvious value (the max brightness 0x3a9) in intel_bios_reader output. > Additionally we could enable the PWM request from ASLE. It would be > interesting to see if there are PWM requests, and with what values, if > you enable drm.debug=0xe and do: > diff --git a/drivers/gpu/drm/i915/intel_opregion.c b/drivers/gpu/drm/i915/intel_opregion.c > index 53a82ea..2b379ec 100644 > --- a/drivers/gpu/drm/i915/intel_opregion.c > +++ b/drivers/gpu/drm/i915/intel_opregion.c > @@ -390,6 +390,7 @@ static u32 asle_set_als_illum(struct drm_device *dev, u32 alsi) > > static u32 asle_set_pwm_freq(struct drm_device *dev, u32 pfmb) > { > + DRM_DEBUG_DRIVER("pfmb = 0x%08x\n", pfmb); > DRM_DEBUG_DRIVER("PWM freq is not supported\n"); > return ASLE_PWM_FREQ_FAILED; > } > @@ -618,7 +619,8 @@ void intel_opregion_init(struct drm_device *dev) > } > > if (opregion->asle) { > - iowrite32(ASLE_TCHE_BLC_EN, &opregion->asle->tche); > + iowrite32(ASLE_TCHE_BLC_EN | ASLE_TCHE_PFMB_EN, > + &opregion->asle->tche); > iowrite32(ASLE_ARDY_READY, &opregion->asle->ardy); > } > } > > Adding support for this is a bit tedious, though, as the PWM value has > been set as the max for the backlight device. It's probably not a good > idea to change the max on the fly in the user space facing interface, so > scaling would be required. With the patch, no useful information showed up, unfortunately. > Note to self, we need to take machines like [1] into account too. Yep, we can't take some value blindly. thanks, Takashi > > > BR, > Jani. > > > [1] http://lkml.kernel.org/r/1347627426-3813-1-git-send-email-grant.likely@secretlab.ca > ---
diff --git a/drivers/gpu/drm/i915/intel_opregion.c b/drivers/gpu/drm/i915/intel_opregion.c index 53a82ea..2b379ec 100644 --- a/drivers/gpu/drm/i915/intel_opregion.c +++ b/drivers/gpu/drm/i915/intel_opregion.c @@ -390,6 +390,7 @@ static u32 asle_set_als_illum(struct drm_device *dev, u32 alsi) static u32 asle_set_pwm_freq(struct drm_device *dev, u32 pfmb) { + DRM_DEBUG_DRIVER("pfmb = 0x%08x\n", pfmb); DRM_DEBUG_DRIVER("PWM freq is not supported\n"); return ASLE_PWM_FREQ_FAILED; } @@ -618,7 +619,8 @@ void intel_opregion_init(struct drm_device *dev) } if (opregion->asle) { - iowrite32(ASLE_TCHE_BLC_EN, &opregion->asle->tche); + iowrite32(ASLE_TCHE_BLC_EN | ASLE_TCHE_PFMB_EN, + &opregion->asle->tche); iowrite32(ASLE_ARDY_READY, &opregion->asle->ardy); } }