[Intel-gfx] i915: slow startup

[Lucas De Marchi]

Hi,

I'm experiencing a longer boot up with recent kernels. Looking at the
kernel log, it seems to be related to the i915 driver. See excerpts of
the logs below:

2.6.38.4:
[    0.533344] Linux agpgart interface v0.103
[    0.533411] agpgart-intel 0000:00:00.0: Intel GM45 Chipset
[    0.533597] agpgart-intel 0000:00:00.0: detected gtt size: 2097152K total, 26
2144K mappable
[    0.534839] agpgart-intel 0000:00:00.0: detected 32768K stolen memory
[    0.534957] agpgart-intel 0000:00:00.0: AGP aperture is 256M @ 0xd0000000
[    0.535023] [drm] Initialized drm 1.1.0 20060810
[    0.535045] i915 0000:00:02.0: PCI INT A -> GSI 16 (level, low) -> IRQ 16
[    0.535050] i915 0000:00:02.0: setting latency timer to 64
[    0.625997] i915 0000:00:02.0: irq 45 for MSI/MSI-X
[    0.626013] [drm] Supports vblank timestamp caching Rev 1 (10.10.2010).
[    0.626015] [drm] Driver supports precise vblank timestamp query.
[    0.704773] composite sync not supported
[    0.706220] fixme: max PWM is zero.
[    0.714167] composite sync not supported
[    0.728223] fbcon: inteldrmfb (fb0) is primary device
[    0.732710] Console: switching to colour frame buffer device 160x50
[    0.735365] fb0: inteldrmfb frame buffer device
[    0.735366] drm: registered panic notifier
[    0.755610] acpi device:06: registered as cooling_device0
[    0.755786] input: Video Bus as
/devices/LNXSYSTM:00/device:00/PNP0A08:00/LNXVIDEO:01/input/input4
[    0.755792] ACPI: Video Device [GFX0] (multi-head: yes  rom: no  post: no)
[    0.755888] [drm] Initialized i915 1.6.0 20080730 for 0000:00:02.0 on minor 0


----------

And for 3.2-rc1 (though 3.1 and 3.0 have similar timings):

[    0.611279] Linux agpgart interface v0.103
[    0.611346] agpgart-intel 0000:00:00.0: Intel GM45 Chipset
[    0.611541] agpgart-intel 0000:00:00.0: detected gtt size: 2097152K total, 26
2144K mappable
[    0.612758] agpgart-intel 0000:00:00.0: detected 32768K stolen memory
[    0.612890] agpgart-intel 0000:00:00.0: AGP aperture is 256M @ 0xd0000000
[    0.612938] [drm] Initialized drm 1.1.0 20060810
[    0.612958] i915 0000:00:02.0: PCI INT A -> GSI 16 (level, low) -> IRQ 16
[    0.612963] i915 0000:00:02.0: setting latency timer to 64
[    0.705279] i915 0000:00:02.0: irq 45 for MSI/MSI-X
[    0.705284] [drm] Supports vblank timestamp caching Rev 1 (10.10.2010).
[    0.705286] [drm] Driver supports precise vblank timestamp query.
[    0.757666] composite sync not supported
[    0.757702] fixme: max PWM is zero.
[    1.220708] composite sync not supported
[    1.239559] fbcon: inteldrmfb (fb0) is primary device
[    1.532030] Refined TSC clocksource calibration: 2194.499 MHz.
[    1.532034] Switching to clocksource tsc
[    1.763692] Console: switching to colour frame buffer device 160x50
[    1.766367] fb0: inteldrmfb frame buffer device
[    1.766368] drm: registered panic notifier
[    1.806045] acpi device:06: registered as cooling_device0
[    1.806169] input: Video Bus as
/devices/LNXSYSTM:00/device:00/PNP0A08:00/LNXVIDEO:01/input/input4
[    1.806175] ACPI: Video Device [GFX0] (multi-head: yes  rom: no  post: no)
[    1.806205] [drm] Initialized i915 1.6.0 20080730 for 0000:00:02.0 on minor 0

----------


While in 2.6.38 the message "[drm] Initialized..." came after 0.75s,
in 3.[012] it's taking 1.8s. These kernels have similar configs, so I
don't think it's because of new features. However I can not be sure
it's intel's driver fault because the log is not much verbose. If I
turn verbose logging, the timings and messages change a lot and it's
difficult to compare those kernels.


Do you know of major changes in the intel driver that might be causing
this delay?


My card is the following one:
00:00.0 Host bridge: Intel Corporation Mobile 4 Series Chipset Memory
Controller Hub (rev 07)
	Subsystem: Dell Device 02bb
	Flags: bus master, fast devsel, latency 0
	Capabilities: <access denied>
	Kernel driver in use: agpgart-intel

00:02.0 VGA compatible controller: Intel Corporation Mobile 4 Series
Chipset Integrated Graphics Controller (rev 07) (prog-if 00 [VGA
controller])
	Subsystem: Dell Device 02bb
	Flags: bus master, fast devsel, latency 0, IRQ 45
	Memory at f6400000 (64-bit, non-prefetchable) [size=4M]
	Memory at d0000000 (64-bit, prefetchable) [size=256M]
	I/O ports at 1800 [size=8]
	Capabilities: <access denied>
	Kernel driver in use: i915

00:02.1 Display controller: Intel Corporation Mobile 4 Series Chipset
Integrated Graphics Controller (rev 07)
	Subsystem: Dell Device 02bb
	Flags: bus master, fast devsel, latency 0
	Memory at f6100000 (64-bit, non-prefetchable) [size=1M]



Thanks
Lucas De Marchi