linux-kernel - atl2: don't mess up irq on suspend/resume (probably msi only)

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Date:	Sun, 16 Nov 2008 12:37:21 +0000
From:	Alan Jenkins <alan-jenkins@...fmail.co.uk>
To:	csnook@...hat.com, atl1-devel@...ts.sourceforge.net
CC:	linux-kernel <linux-kernel@...r.kernel.org>
Subject: atl2: don't mess up irq on suspend/resume (probably msi only)

According to Documentation/power/pci.txt, the correct suspend sequence is:

    A reference implementation
    -------------------------
    .suspend()
    {
        /* driver specific operations */

        /* Disable IRQ */
        free_irq();
        /* If using MSI */
        pci_disable_msi();

        pci_save_state();
        pci_enable_wake();
        /* Disable IO/bus master/irq router */
        pci_disable_device();
        pci_set_power_state(pci_choose_state());
    }


Whereas atl2 calls pci_save_state() *before* free_irq() and
pci_disable_msi().  Hilarity ensues on resume as pci_restore_state()
restores a state with MSI enabled; the atl2 resume handler then enables
msi for the second time.  Looking at /proc/interrupts, it seems to leak
an irq each time this happens.  (I had 6 entries for "eth0" by the time
I noticed this).  It also triggers a warning.

I was able to avoid the warning + leak by re-ordering the resume
method.  Patch attached - it's just a few lines, I hope that's all
that's necessary.

------------[ cut here ]------------
WARNING: at drivers/pci/msi.c:570 pci_enable_msi+0x3a/0x1cd()
Modules linked in: cpufreq_stats freq_table nls_iso8859_1 nls_cp437 vfat fat rfkill_input ae
Pid: 2620, comm: NetworkManager Tainted: G        W  2.6.28-rc4eeepc #136
Call Trace:
 [<c011b89a>] warn_on_slowpath+0x40/0x59
 [<c023df15>] raw_pci_read+0x4d/0x55
 [<c023dff3>] pci_read+0x1c/0x21
 [<c01bcd81>] __pci_find_next_cap_ttl+0x44/0x70
 [<c01bce86>] __pci_find_next_cap+0x1a/0x1f
 [<c01bcef9>] pci_find_capability+0x28/0x2c
 [<c01c4144>] pci_msi_check_device+0x53/0x62
 [<c01c49c2>] pci_enable_msi+0x3a/0x1cd
 [<e019f17b>] atl2_write_phy_reg+0x40/0x5f [atl2]
 [<c01061b1>] dma_generic_alloc_coherent+0x0/0xd7
 [<e019f107>] atl2_request_irq+0x15/0x49 [atl2]
 [<e01a1481>] atl2_open+0x20b/0x297 [atl2]
 [<c024a35c>] dev_open+0x62/0x91
 [<c0248b9a>] dev_change_flags+0x93/0x141
 [<c024f308>] do_setlink+0x238/0x2d5
 [<c02501b2>] rtnl_setlink+0xa9/0xbf
 [<c0297f0c>] mutex_lock+0xb/0x19
 [<c024ffa7>] rtnl_dump_ifinfo+0x0/0x69
 [<c0250109>] rtnl_setlink+0x0/0xbf
 [<c024fe42>] rtnetlink_rcv_msg+0x185/0x19f
 [<c0240fd1>] sock_rmalloc+0x23/0x57
 [<c024fcbd>] rtnetlink_rcv_msg+0x0/0x19f
 [<c0259457>] netlink_rcv_skb+0x2d/0x71
 [<c024fcb7>] rtnetlink_rcv+0x14/0x1a
 [<c025929e>] netlink_unicast+0x184/0x1e4
 [<c025992a>] netlink_sendmsg+0x233/0x240
 [<c023f405>] sock_sendmsg+0xb7/0xd0
 [<c0129131>] autoremove_wake_function+0x0/0x2b
 [<c0129131>] autoremove_wake_function+0x0/0x2b
 [<c0147796>] mempool_alloc+0x2d/0x9e
 [<c020c923>] scsi_pool_alloc_command+0x35/0x4f
 [<c0297f0c>] mutex_lock+0xb/0x19
 [<c028e867>] unix_stream_recvmsg+0x357/0x3e2
 [<c01b81c9>] copy_from_user+0x23/0x4f
 [<c02452ea>] verify_iovec+0x3e/0x6c
 [<c023f5ab>] sys_sendmsg+0x18d/0x1f0
 [<c023ffa8>] sys_recvmsg+0x146/0x1c8
 [<c0240016>] sys_recvmsg+0x1b4/0x1c8
 [<c0118f48>] __wake_up+0xf/0x15
 [<c02586cd>] netlink_table_ungrab+0x17/0x19
 [<c01b83ba>] copy_to_user+0x25/0x3b
 [<c023fe4a>] move_addr_to_user+0x50/0x68
 [<c0240266>] sys_getsockname+0x6f/0x9a
 [<c0240280>] sys_getsockname+0x89/0x9a
 [<c015046a>] do_wp_page+0x3ae/0x41a
 [<c0151525>] handle_mm_fault+0x4c5/0x540
 [<c02405d0>] sys_socketcall+0x176/0x1b0
 [<c010376d>] sysenter_do_call+0x12/0x21
---[ end trace ad80134e35e20aad ]---





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