On Sun, May 20, 2007 11:54, Tejun Heo wrote: > Indan Zupancic wrote: >> On Sat, May 19, 2007 21:04, Tejun Heo wrote: >>> Tejun Heo wrote: >>>> Yeah, if SCR registers are accessible, 0xff doesn't indicate the device >>>> isn't there, so the whole skip-0xff logic probably shouldn't apply in >>>> such cases, but we can also achieve pretty good result by just making >>>> the first reset tries a bit more aggressive. >>> So, here's the patch. >>> >>> Paul, can you please test this patch without the previous patch? Indan, >>> this should reduce the resume delay. Please test. But you'll still >>> feel some added delay compared to 2.6.20 due to the mentioned >>> suspend/resume change. >> >> This removed the COMRESET errors indeed, and with sd_resume() >> disabled everything is speedy again (2s or so. Still a desktop pc). >> I didn't try with sd_resume enabled. > > Can you try to measure with sd_resume in place? [ 2.173366] sd 0:0:0:0: [sda] Starting disk [ 2.475422] ata2: SATA link down (SStatus 0 SControl 310) [ 5.478403] ata1: SATA link up 1.5 Gbps (SStatus 113 SControl 310) [ 5.481928] ata1.00: ata_hpa_resize 1: sectors = 234441648, hpa_sectors = 234441648 [ 5.485904] ata1.00: ata_hpa_resize 1: sectors = 234441648, hpa_sectors = 234441648 [ 5.485913] ata1.00: configured for UDMA/100 [ 5.505109] sd 0:0:0:0: [sda] 234441648 512-byte hardware sectors (120034 MB) [ 5.505461] sd 0:0:0:0: [sda] Write Protect is off [ 5.505465] sd 0:0:0:0: [sda] Mode Sense: 00 3a 00 00 [ 5.505612] sd 0:0:0:0: [sda] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA ... [ 6.157259] Restarting tasks ... done. And with echo 0 > /sys/class/scsi_disk/0\:0\:0\:0/manage_start_stop: [ 2.476476] ata2: SATA link down (SStatus 0 SControl 310) ... [ 2.825479] Restarting tasks ... done. ... [ 5.022076] ata1: SATA link up 1.5 Gbps (SStatus 113 SControl 310) [ 5.025605] ata1.00: ata_hpa_resize 1: sectors = 234441648, hpa_sectors = 234441648 [ 5.028594] ata1.00: ata_hpa_resize 1: sectors = 234441648, hpa_sectors = 234441648 [ 5.028606] ata1.00: configured for UDMA/100 [ 5.028720] sd 0:0:0:0: [sda] 234441648 512-byte hardware sectors (120034 MB) [ 5.028767] sd 0:0:0:0: [sda] Write Protect is off [ 5.028773] sd 0:0:0:0: [sda] Mode Sense: 00 3a 00 00 [ 5.028831] sd 0:0:0:0: [sda] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA So over all it takes half a second longer to detect the disk, but because everything waits on it, it takes more than three seconds longer to resume. Setting manage_start_stop to 0 fixes it and is good enough for me, I didn't notice anything bad yet because of the unmanaged stop. Implementing background spin up will fix it too. >> Everything seems to work fine without sd_resume(), so why is it needed? > > Because not all disks spin up without being told to do so and like it or > not spinning disks up on resume is the default behavior. As I wrote in > the other reply, it would be worthwhile to make it configurable. Not even after they receive a read command? Ugh. Greeting, Indan - 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
