Date:	Mon, 17 Nov 2008 21:43:16 +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: Re: atl2: don't mess up irq on suspend/resume (probably msi only)

Alan Jenkins wrote:
> 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.
>   

Don't listen to me.  The problem went away because when I was testing my
patch, I plugged the ethernet in and actually used it.  My patch doesn't
seem to fix anything.

So I now have the steps to reproduce this warning: remove the ethernet
cable and suspend.

Also, I was speaking rubbish because the warning isn't on the resume
path.  It seems to be when network-manager re-opens the device on resume.

I'll have another look for possible culprits.  Hints appreciated :).

> ------------[ 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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