Hi,
When the CONFIG_TMPFS is cleared in kernel configuration, it seems that the i915 driver can't be loaded correctly.
Is this a known issue?
         The following is the corresponding backtrace info when the kernel panic happens. The full dmesg info is also attached.

[    4.263407] [drm] set up 7M of stolen space
[    4.267606] BUG: unable to handle kernel NULL pointer dereference at (null)
[    4.271577] IP: [<(null)>] (null)
[    4.271577] PGD 0
[    4.271577] Oops: 0010 [#1] SMP
[    4.271577] last sysfs file:
[    4.271577] CPU 1
[    4.271577] Pid: 1, comm: swapper Not tainted 2.6.33 #31 0A58h/HP Compaq dc7700p Convertible Minitower
[    4.271577] RIP: 0010:[<0000000000000000>]  [<(null)>] (null)
[    4.271577] RSP: 0018:ffff88007d801a38  EFLAGS: 00010246
[    4.271577] RAX: 0000000000000000 RBX: ffffea0000c3da60 RCX: 0000000000000010
[    4.271577] RDX: 0000000000000012 RSI: ffffea0000c3da60 RDI: 0000000000000000
[    4.271577] RBP: ffff88007d801a80 R08: 0000000000000080 R09: ffffea0000c3da60
[    4.271577] R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000000
[    4.271577] R13: 0000000000000000 R14: ffff88007cb73e48 R15: 0000000000000000
[    4.271577] FS:  0000000000000000(0000) GS:ffff880001d00000(0000) knlGS:0000000000000000
[    4.271577] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[    4.271577] CR2: 0000000000000000 CR3: 0000000001779000 CR4: 00000000000006e0
[    4.271577] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[    4.271577] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
[    4.271577] Process swapper (pid: 1, threadinfo ffff88007d800000, task ffff88007e3ff390)
[    4.271577] Stack:
[    4.271577]  ffffffff8109d3b8 ffff88007d801a90 000213da00000246 0000000000000000
[    4.271577] <0> ffff88007c82a500 0000000000000000 0000000000000000 ffff88007c82a5c0
[    4.271577] <0> ffff88007cb73e48 ffff88007d801a90 ffffffff8109d471 ffff88007d801af0
[    4.271577] Call Trace:
[    4.271577]  [<ffffffff8109d3b8>] ? do_read_cache_page+0x95/0x131
[    4.271577]  [<ffffffff8109d471>] read_cache_page_gfp+0x1d/0x27
[    4.271577]  [<ffffffff812c3231>] i915_gem_object_get_pages+0xdb/0x128
[    4.271577]  [<ffffffff812b0ecc>] ? drm_mm_get_block_generic+0x80/0x9e
[    4.271577]  [<ffffffff812c4936>] i915_gem_object_bind_to_gtt+0x16a/0x286
[    4.271577]  [<ffffffff812c4a7e>] i915_gem_object_pin+0x2c/0x9c
[    4.271577]  [<ffffffff812c4cc9>] i915_gem_init_ringbuffer+0x1db/0x4a5
[    4.271577]  [<ffffffff812ba755>] i915_driver_load+0x731/0xa41
[    4.271577]  [<ffffffff812eb819>] ? device_register+0x1e/0x22
[    4.271577]  [<ffffffff812af202>] ? drm_sysfs_device_add+0x8c/0xaf
[    4.271577]  [<ffffffff812ace8f>] ? drm_get_minor+0x27f/0x2cf
[    4.271577]  [<ffffffff812ad2bd>] drm_get_dev+0x3de/0x4d1
[    4.271577]  [<ffffffff814a00cd>] i915_pci_probe+0x15/0x17
[    4.271577]  [<ffffffff81215165>] local_pci_probe+0x17/0x1b
[    4.271577]  [<ffffffff812159f7>] pci_device_probe+0xcb/0xf5
[    4.271577]  [<ffffffff812eda14>] ? driver_sysfs_add+0x51/0x77
[    4.271577]  [<ffffffff812edbbd>] driver_probe_device+0xe3/0x1ac
[    4.271577]  [<ffffffff812edce3>] __driver_attach+0x5d/0x80
[    4.271577]  [<ffffffff812edc86>] ? __driver_attach+0x0/0x80
[    4.271577]  [<ffffffff812ed30e>] bus_for_each_dev+0x53/0x89
[    4.271577]  [<ffffffff812ed98b>] driver_attach+0x21/0x23
[    4.271577]  [<ffffffff812ecbb7>] bus_add_driver+0x11b/0x271
[    4.271577]  [<ffffffff812edfe6>] driver_register+0xb8/0x126
[    4.271577]  [<ffffffff8187f013>] ? i915_init+0x0/0x52
[    4.271577]  [<ffffffff81215c58>] __pci_register_driver+0x56/0xc1
[    4.271577]  [<ffffffff8187f013>] ? i915_init+0x0/0x52
[    4.271577]  [<ffffffff812a827c>] drm_init+0x6b/0xd1
[    4.271577]  [<ffffffff8187f013>] ? i915_init+0x0/0x52
[    4.271577]  [<ffffffff8187f063>] i915_init+0x50/0x52
[    4.271577]  [<ffffffff810001fa>] do_one_initcall+0x5f/0x154
[    4.271577]  [<ffffffff8185964c>] kernel_init+0x141/0x197
[    4.271577]  [<ffffffff81003954>] kernel_thread_helper+0x4/0x10
[    4.271577]  [<ffffffff814bdbe9>] ? restore_args+0x0/0x30
[    4.271577]  [<ffffffff8185950b>] ? kernel_init+0x0/0x197
[    4.271577]  [<ffffffff81003950>] ? kernel_thread_helper+0x0/0x10
[    4.271577] Code:  Bad RIP value.
[    4.271577] RIP  [<(null)>] (null)
[    4.271577]  RSP <ffff88007d801a38>
[    4.271577] CR2: 0000000000000000
[    4.627944] ---[ end trace 5c25bb18f839b05e ]---

Best regards.
    Yakui