Sony Vaio VGN-P and T2/Linux
The Sony Vaio VGN-P is a very slim, lightweight and stylish, however "very expensive" sub-notebook that just weights about 620 grams.
Powered by the ULV (Ultra Low Volage) version of the Intel Atom (Z5xx) and new Pulsbo (US15W) chipset it even achieves over 3 hours of battery time with the standard battery, and up to about 8 hours with and optional, extended battery, despite the small size.
Notes
Suspend to RAM did not came back properly on a test machine - though it might with some VBE re-POST glue.
In a quick test the WWAN modem did not show up, although it is listed under "the other OS" as: Option Globetrotter GE40x (0x0af0, 0x7601). It might come up after fiddeling with: /sys/devices/platform/sony-acpi/wwanpower, ...
The machine lacks a digital video output (like DVI / HDMI) - the custom extension port with video out and ethernet only wires out VGA.
Accelerated video is not yet available in an open source form due ot the PowerVR based Intel GMA 500, Pulsbo, chipset.
It looks like the tested machine was an early prototype, the retail version appears to disable the VT of the Intel Z-series Atom in the BIOS, which might be possible to circumvent with some BIOS NVRAM value poking.
Performance Index
31:35m to build binutils-2.41 w/ gcc-4.5 (no-LTO, -O2), linux-4.6.31
3:57m to build bash-5.2-015 w/ gcc-4.5 (no-LTO, -O2), linux-2.6.31
30s to build lua-5.4.6 w/ gcc-4.5 (no-LTO, -O2), linux-2.6.31
/proc/cpuinfo
vendor_id : GenuineIntel
cpu family : 6
model : 28
model name : Intel(R) Atom(TM) CPU Z550 @ 2.00GHz
stepping : 2
cpu MHz : 800.000
cache size : 512 KB
physical id : 0
siblings : 2
core id : 0
cpu cores : 1
apicid : 0
initial apicid : 0
fdiv_bug : no
hlt_bug : no
f00f_bug : no
coma_bug : no
fpu : yes
fpu_exception : yes
cpuid level : 10
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic mtrr pge mca cmov pat clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe nx constant_tsc arch_perfmon pebs bts pni dtes64 monitor ds_cpl vmx est tm2 ssse3 xtpr pdcm movbe lahf_lm tpr_shadow vnmi flexpriority
bogomips : 3999.54
clflush size : 64
power management:
processor : 1
vendor_id : GenuineIntel
cpu family : 6
model : 28
model name : Intel(R) Atom(TM) CPU Z550 @ 2.00GHz
stepping : 2
cpu MHz : 800.000
cache size : 512 KB
physical id : 0
siblings : 2
core id : 0
cpu cores : 1
apicid : 1
initial apicid : 1
fdiv_bug : no
hlt_bug : no
f00f_bug : no
coma_bug : no
fpu : yes
fpu_exception : yes
cpuid level : 10
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic mtrr pge mca cmov pat clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe nx constant_tsc arch_perfmon pebs bts pni dtes64 monitor ds_cpl vmx est tm2 ssse3 xtpr pdcm movbe lahf_lm tpr_shadow vnmi flexpriority
bogomips : 3999.75
clflush size : 64
power management:
lspci
0000:00:02.0 VGA compatible controller: Intel Corporation System Controller Hub (SCH Poulsbo) Graphics Controller (rev 06)
0000:00:1b.0 Audio device: Intel Corporation System Controller Hub (SCH Poulsbo) HD Audio Controller (rev 06)
0000:00:1c.0 PCI bridge: Intel Corporation System Controller Hub (SCH Poulsbo) PCI Express Port 1 (rev 06)
0000:00:1c.1 PCI bridge: Intel Corporation System Controller Hub (SCH Poulsbo) PCI Express Port 2 (rev 06)
0000:00:1d.0 USB Controller: Intel Corporation System Controller Hub (SCH Poulsbo) USB UHCI #1 (rev 06)
0000:00:1d.1 USB Controller: Intel Corporation System Controller Hub (SCH Poulsbo) USB UHCI #2 (rev 06)
0000:00:1d.2 USB Controller: Intel Corporation System Controller Hub (SCH Poulsbo) USB UHCI #3 (rev 06)
0000:00:1d.7 USB Controller: Intel Corporation System Controller Hub (SCH Poulsbo) USB EHCI #1 (rev 06)
0000:00:1f.0 ISA bridge: Intel Corporation System Controller Hub (SCH Poulsbo) LPC Bridge (rev 06)
0000:00:1f.1 IDE interface: Intel Corporation System Controller Hub (SCH Poulsbo) IDE Controller (rev 06)
0000:01:00.0 Ethernet controller: Marvell Technology Group Ltd. Device 4380 (rev 10)
0000:02:00.0 Network controller: Atheros Communications Inc. AR928X Wireless Network Adapter (PCI-Express) (rev 01)
lsusb
Bus 004 Device 001: ID 1d6b:0002
Bus 003 Device 001: ID 1d6b:0001
Bus 002 Device 002: ID 044e:3017 Alps Electric Co.
Bus 002 Device 001: ID 1d6b:0001
Bus 001 Device 001: ID 1d6b:0001