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  • Reinette Chatre's avatar
    iwlagn: power up device before initializing EEPROM · e43ab94d
    Reinette Chatre authored
    
    
    A recent change optimized the power usage by the device by only powering it
    up during EEPROM load if it is required (for OTP devices). This change causes
    an error on the 1000 series devices during module load.
    
    The error looks as follows:
    [ 1624.024524] iwlagn: Intel(R) Wireless WiFi Link AGN driver for Linux, 1.3.27kds
    [ 1624.024527] iwlagn: Copyright(c) 2003-2009 Intel Corporation
    [ 1624.024711] iwlagn 0000:01:00.0: PCI INT A -> GSI 16 (level, low) -> IRQ 16
    [ 1624.024749] iwlagn 0000:01:00.0: setting latency timer to 64
    [ 1624.024909] iwlagn 0000:01:00.0: Detected Intel Wireless WiFi Link 1000 Series BGN REV=0x6C
    [ 1624.081263] iwlagn 0000:01:00.0: MAC is in deep sleep!.  CSR_GP_CNTRL = 0x080003D8
    [ 1624.092967] iwlagn 0000:01:00.0: OTP is empty
    [ 1624.092988] iwlagn 0000:01:00.0: Unable to init EEPROM
    [ 1624.093033] iwlagn 0000:01:00.0: PCI INT A disabled
    [ 1624.093065] iwlagn: probe of 0000:01:00.0 failed with error -2
    
    Adding a dump_stack() to where that error is printed shows the following:
    
    [ 1624.024524] iwlagn: Intel(R) Wireless WiFi Link AGN driver for Linux, 1.3.27kds
    [ 1624.024527] iwlagn: Copyright(c) 2003-2009 Intel Corporation
    [ 1624.024711] iwlagn 0000:01:00.0: PCI INT A -> GSI 16 (level, low) -> IRQ 16
    [ 1624.024749] iwlagn 0000:01:00.0: setting latency timer to 64
    [ 1624.024909] iwlagn 0000:01:00.0: Detected Intel Wireless WiFi Link 1000 Series BGN REV=0x6C
    [ 1624.081263] iwlagn 0000:01:00.0: MAC is in deep sleep!.  CSR_GP_CNTRL = 0x080003D8
    [ 1624.081263] Pid: 3073, comm: work_for_cpu Tainted: G        W 2.6.31.5 #4
    [ 1624.081263] Call Trace:
    [ 1624.081263]  [<ffffffffa02395db>] T.726+0x22b/0x420 [iwlcore]
    [ 1624.081263]  [<ffffffffa023985a>] iwlcore_eeprom_acquire_semaphore+0x8a/0x190 [iwlcore]
    [ 1624.081263]  [<ffffffff81110c94>] ? __kmalloc+0x194/0x1c0
    [ 1624.081263]  [<ffffffffa02391f5>] ?  iwlcore_eeprom_verify_signature+0x25/0xf0 [iwlcore]
    [ 1624.081263]  [<ffffffffa0239c67>] iwl_eeprom_init+0x107/0xf40 [iwlcore]
    [ 1624.081263]  [<ffffffffa026ab9c>] ?  iwl_prepare_card_hw+0x11c/0x470 [iwlagn]
    [ 1624.081263]  [<ffffffff8127e2a4>] ?  pci_bus_write_config_byte+0x64/0x80
    [ 1624.081263]  [<ffffffffa026b1f8>] iwl_pci_probe+0x308/0xac0 [iwlagn]
    [ 1624.081263]  [<ffffffff810710a0>] ? do_work_for_cpu+0x0/0x30
    [ 1624.081263]  [<ffffffff81284912>] local_pci_probe+0x12/0x20
    [ 1624.081263]  [<ffffffff810710b3>] do_work_for_cpu+0x13/0x30
    [ 1624.081263]  [<ffffffff81075826>] kthread+0xa6/0xb0
    [ 1624.081263]  [<ffffffff81012fea>] child_rip+0xa/0x20
    [ 1624.081263]  [<ffffffff81075780>] ? kthread+0x0/0xb0
    [ 1624.081263]  [<ffffffff81012fe0>] ? child_rip+0x0/0x20
    [ 1624.092967] iwlagn 0000:01:00.0: OTP is empty
    [ 1624.092988] iwlagn 0000:01:00.0: Unable to init EEPROM
    [ 1624.093033] iwlagn 0000:01:00.0: PCI INT A disabled
    [ 1624.093065] iwlagn: probe of 0000:01:00.0 failed with error -2
    
    We know that the routines in this trace, iwlcore_eeprom_acquire_semaphore
    and iwlcore_eeprom_verify_signature, only access CSR registers and thus do
    not need the device to be awake if it is EEPROM. But for OTP it is required
    for the device to be awake to read these registers. Ensure device is awake
    before accessing these registers.
    
    Signed-off-by: default avatarReinette Chatre <reinette.chatre@intel.com>
    Acked-by: default avatarBen Cahill <ben.m.cahill@intel.com>
    Signed-off-by: default avatarJohn W. Linville <linville@tuxdriver.com>
    e43ab94d