Simon Farnsworth wrote: > Hello, > > We're trying to consistently disable write caching on our systems (one > PATA disk on /dev/sda), by running the following command during boot: > > hdparm -W0 /dev/sda > > However, on some disks, we see a freeze of between 30 seconds and 2 > minutes after issuing this command. How do we avoid this freeze? We're > happy to write our own userspace utility, or change the kernel. > > We're using the pata_via driver, with a kernel that's the same code as > the Fedora 3189 kernel, but with CONFIG_DEBUG_STACKOVERFLOW set to n. > > From a machine that's just done this freeze: [--snip--] > BUG: warning at kernel/softirq.c:138/local_bh_enable() (Not tainted) > [<c042afff>] local_bh_enable+0x45/0x96 > [<c0603cde>] cond_resched_softirq+0x2d/0x43 > [<c05d55bf>] established_get_first+0x17/0xac > [<c05d8f93>] tcp_seq_next+0x71/0x86 > [<c048c004>] seq_read+0x181/0x268 > [<c048be83>] seq_read+0x0/0x268 > [<c0476651>] vfs_read+0xab/0x15a > [<c0476fb7>] sys_read+0x41/0x67 > [<c0404ecc>] syscall_call+0x7/0xb > ======================= Hmmmm.. This is the only suspicious looking part of the kernel log and doesn't have too much to do with ATA freeze. 30sec - 2min delay sounds awfully like something caused by ATA commands timing out but libata always complains verbosely about those. Can you check dmesg again after the freeze? -- tejun - To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
