[Intel-gfx] No boot console/Plane B assertion value on 945GM hardware

[Daniel Vetter]

On Sat, Jun 21, 2014 at 01:57:32PM +0200, Thomas Richter wrote:
> Hi Daniel, dear intel experts,
> 
> this a bug report for the intel i945GM integrated graphics chipset (*NOT*
> the 830GM this time). Since at least 3.12.0, but also with the latest
> intel-drm-nightly, I have no boot console on the 945GM chipset, the screen
> just remains blank. /var/log/messages  shows an assertion failure, see the
> attached kernel log for details, booted with drm.debug=0x0e.
> 
> The problem appears if the kernel is booted with the vga=792 option  - note
> that the panel in this laptop is a 1024x768 and thus this is the native
> resolution. The problem does not appear with a text console.
> 
> This sounds remarkably similar to the deadlock the 830GM had a while ago
> when booting with a graphical console, also with vga=792.

Should be unrelated - more likely it's some fumble in the modeset
sequence, i945 is known to be picky in that area. Just to confirm: Latest
3.16-rc kernels are still broken?

> This is the kernel warning:
> 
> Jun 21 13:44:26 kahvi kernel: [    4.780120] WARNING: CPU: 1 PID: 239 at
> drivers/gpu/drm/i915/intel_display.c:1307 assert_planes_disabled+0x110/0x160
> [i915]()
> Jun 21 13:44:26 kahvi kernel: [    4.780126] plane B assertion failure,
> should be off on pipe B but is still active

Can you please boot with drm.debug=0xe and grab a new dmesg with the
backtrace?

> The machine is a Fujitsu Siemens T4215. lspci lists the following hardware:
> 
> 00:00.0 Host bridge: Intel Corporation Mobile 945GM/PM/GMS, 943/940GML and
> 945GT Express Memory Controller Hub (rev 03)
> 00:02.0 VGA compatible controller: Intel Corporation Mobile 945GM/GMS,
> 943/940GML Express Integrated Graphics Controller (rev 03)
> 00:02.1 Display controller: Intel Corporation Mobile 945GM/GMS/GME,
> 943/940GML Express Integrated Graphics Controller (rev 03)
> 00:1b.0 Audio device: Intel Corporation NM10/ICH7 Family High Definition
> Audio Controller (rev 02)
> 00:1c.0 PCI bridge: Intel Corporation NM10/ICH7 Family PCI Express Port 1
> (rev 02)
> 00:1c.1 PCI bridge: Intel Corporation NM10/ICH7 Family PCI Express Port 2
> (rev 02)
> 00:1c.2 PCI bridge: Intel Corporation NM10/ICH7 Family PCI Express Port 3
> (rev 02)
> 00:1d.0 USB controller: Intel Corporation NM10/ICH7 Family USB UHCI
> Controller #1 (rev 02)
> 00:1d.1 USB controller: Intel Corporation NM10/ICH7 Family USB UHCI
> Controller #2 (rev 02)
> 00:1d.2 USB controller: Intel Corporation NM10/ICH7 Family USB UHCI
> Controller #3 (rev 02)
> 00:1d.3 USB controller: Intel Corporation NM10/ICH7 Family USB UHCI
> Controller #4 (rev 02)
> 00:1d.7 USB controller: Intel Corporation NM10/ICH7 Family USB2 EHCI
> Controller (rev 02)
> 00:1e.0 PCI bridge: Intel Corporation 82801 Mobile PCI Bridge (rev e2)
> 00:1f.0 ISA bridge: Intel Corporation 82801GBM (ICH7-M) LPC Interface Bridge
> (rev 02)
> 00:1f.1 IDE interface: Intel Corporation 82801G (ICH7 Family) IDE Controller
> (rev 02)
> 00:1f.2 SATA controller: Intel Corporation 82801GBM/GHM (ICH7-M Family) SATA
> Controller [AHCI mode] (rev 02)
> 00:1f.3 SMBus: Intel Corporation NM10/ICH7 Family SMBus Controller (rev 02)
> 02:00.0 Ethernet controller: Marvell Technology Group Ltd. 88E8055 PCI-E
> Gigabit Ethernet Controller (rev 12)
> 05:00.0 Network controller: Intel Corporation PRO/Wireless 4965 AG or AGN
> [Kedron] Network Connection (rev 61)
> 08:03.0 CardBus bridge: O2 Micro, Inc. OZ711MP1/MS1 MemoryCardBus Controller
> (rev 20)
> 08:03.1 CardBus bridge: O2 Micro, Inc. OZ711MP1/MS1 MemoryCardBus Controller
> (rev 20)
> 08:03.2 SD Host controller: O2 Micro, Inc. Integrated MMC/SD Controller
> 08:03.3 Bridge: O2 Micro, Inc. Integrated MS/xD Controller
> 
> As soon as X is initialized, graphics work again, I just don't have a boot
> console.

So once X is running fbcon also works again, i.e. it's only the initial
boot console that's black?

Thanks, Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch