Distribution: Gentoo Linux
Hardware Environment: HP Compaq nx6125 with AMD Turion 64
Problem Description:
After I boot the laptop which has a Broadcom BCM4318 wireless adapter:

02:02.0 Network controller: Broadcom Corporation BCM4318 [AirForce One 54g] 
802.11g Wireless LAN Controller (rev 02)
        Subsystem: Hewlett-Packard Company MX6125
        Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- 
Stepping- SERR- FastB2B-
        Status: Cap- 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- 
<MAbort- >SERR- <PERR-
        Latency: 64
        Interrupt: pin A routed to IRQ 20
        Region 0: Memory at d0010000 (32-bit, non-prefetchable) [size=8K]

I get these messages in dmesg output:

bcm43xx: PHY connected
bcm43xx: Radio turned on
bcm43xx: ASSERTION FAILED (radio_attenuation < 10) at: 
drivers/net/wireless/bcm43xx/bcm43xx_phy.c:1490:bcm43xx_find_lopair()
bcm43xx: WARNING: Writing invalid LOpair (low: -29, high: -41, index: 134)
 [<c0103afb>] show_trace+0x1b/0x20
 [<c0104226>] dump_stack+0x26/0x30
 [<d8bbaf0f>] bcm43xx_phy_lo_adjust+0xbf/0x390 [bcm43xx]
 [<d8bb5170>] bcm43xx_radio_set_txpower_bg+0x1a0/0x340 [bcm43xx]
 [<d8bba16b>] bcm43xx_phy_initb6+0x29b/0xb70 [bcm43xx]
 [<d8bbc548>] bcm43xx_phy_initg+0x458/0x1340 [bcm43xx]
 [<d8bbe6a8>] bcm43xx_phy_init+0x398/0x930 [bcm43xx]
 [<d8ba9c4f>] bcm43xx_chip_init+0x61f/0xa80 [bcm43xx]
 [<d8babd73>] bcm43xx_init_board+0x163/0xe80 [bcm43xx]
 [<d8bad400>] bcm43xx_net_open+0x10/0x20 [bcm43xx]
 [<c03ee56c>] dev_open+0x3c/0x80
 [<c03ecee5>] dev_change_flags+0x55/0x130
 [<c042a75b>] devinet_ioctl+0x50b/0x680
 [<c042b078>] inet_ioctl+0x88/0xb0
 [<c03e1e29>] sock_ioctl+0x149/0x250
 [<c017f675>] do_ioctl+0x35/0xa0
 [<c017f73a>] vfs_ioctl+0x5a/0x300
 [<c017fa21>] sys_ioctl+0x41/0x60
 [<c010298d>] sysenter_past_esp+0x56/0x8d
bcm43xx: ASSERTION FAILED (radio_attenuation < 10) at: 
drivers/net/wireless/bcm43xx/bcm43xx_phy.c:1490:bcm43xx_find_lopair()
bcm43xx: WARNING: Writing invalid LOpair (low: -29, high: -41, index: 134)
 [<c0103afb>] show_trace+0x1b/0x20
 [<c0104226>] dump_stack+0x26/0x30
 [<d8bbaf0f>] bcm43xx_phy_lo_adjust+0xbf/0x390 [bcm43xx]
 [<d8bbc3d0>] bcm43xx_phy_initg+0x2e0/0x1340 [bcm43xx]
 [<d8bbe6a8>] bcm43xx_phy_init+0x398/0x930 [bcm43xx]
 [<d8ba9c4f>] bcm43xx_chip_init+0x61f/0xa80 [bcm43xx]
 [<d8babd73>] bcm43xx_init_board+0x163/0xe80 [bcm43xx]
 [<d8bad400>] bcm43xx_net_open+0x10/0x20 [bcm43xx]
 [<c03ee56c>] dev_open+0x3c/0x80
 [<c03ecee5>] dev_change_flags+0x55/0x130
 [<c042a75b>] devinet_ioctl+0x50b/0x680
 [<c042b078>] inet_ioctl+0x88/0xb0
 [<c03e1e29>] sock_ioctl+0x149/0x250
 [<c017f675>] do_ioctl+0x35/0xa0
 [<c017f73a>] vfs_ioctl+0x5a/0x300
 [<c017fa21>] sys_ioctl+0x41/0x60
 [<c010298d>] sysenter_past_esp+0x56/0x8d
bcm43xx: ASSERTION FAILED (radio_attenuation < 10) at: 
drivers/net/wireless/bcm43xx/bcm43xx_phy.c:1490:bcm43xx_find_lopair()
bcm43xx: WARNING: Writing invalid LOpair (low: -29, high: -41, index: 134)
 [<c0103afb>] show_trace+0x1b/0x20
 [<c0104226>] dump_stack+0x26/0x30
 [<d8bbaf0f>] bcm43xx_phy_lo_adjust+0xbf/0x390 [bcm43xx]
 [<d8bb5170>] bcm43xx_radio_set_txpower_bg+0x1a0/0x340 [bcm43xx]
 [<d8bb939f>] bcm43xx_phy_init_pctl+0x14f/0x330 [bcm43xx]
 [<d8bbc34c>] bcm43xx_phy_initg+0x25c/0x1340 [bcm43xx]
 [<d8bbe6a8>] bcm43xx_phy_init+0x398/0x930 [bcm43xx]
 [<d8ba9c4f>] bcm43xx_chip_init+0x61f/0xa80 [bcm43xx]
 [<d8babd73>] bcm43xx_init_board+0x163/0xe80 [bcm43xx]
 [<d8bad400>] bcm43xx_net_open+0x10/0x20 [bcm43xx]
 [<c03ee56c>] dev_open+0x3c/0x80
 [<c03ecee5>] dev_change_flags+0x55/0x130
 [<c042a75b>] devinet_ioctl+0x50b/0x680
 [<c042b078>] inet_ioctl+0x88/0xb0
 [<c03e1e29>] sock_ioctl+0x149/0x250
 [<c017f675>] do_ioctl+0x35/0xa0
 [<c017f73a>] vfs_ioctl+0x5a/0x300
 [<c017fa21>] sys_ioctl+0x41/0x60
 [<c010298d>] sysenter_past_esp+0x56/0x8d
bcm43xx: Chip initialized
bcm43xx: DMA initialized
bcm43xx: 80211 cores initialized
bcm43xx: Keys cleared
bcm43xx: ASSERTION FAILED (radio_attenuation < 10) at: 
drivers/net/wireless/bcm43xx/bcm43xx_phy.c:1490:bcm43xx_find_lopair()
bcm43xx: WARNING: Writing invalid LOpair (low: -29, high: -41, index: 134)
 [<c0103afb>] show_trace+0x1b/0x20
 [<c0104226>] dump_stack+0x26/0x30
 [<d8bbaf0f>] bcm43xx_phy_lo_adjust+0xbf/0x390 [bcm43xx]
 [<d8bbb8d5>] bcm43xx_phy_lo_g_measure+0x6f5/0xf10 [bcm43xx]
 [<d8bae95f>] bcm43xx_periodic_work_handler+0x1cf/0x4b0 [bcm43xx]
 [<c012abbe>] run_workqueue+0x7e/0x100
 [<c012b2ff>] worker_thread+0x13f/0x160
 [<c012e479>] kthread+0xe9/0xf0
 [<c0100795>] kernel_thread_helper+0x5/0x10