Hi Henry, æ äï2010-12-08 æ 17:56 +0000ïjoeyli(Joey Lee) æåï > Hi Tejun, > > Nice can talk with you! :-) > > æ äï2010-12-08 æ 18:25 +0100ïTejun Heo æåï > > (cc'ing linux-ide) > > > > Hello, > > > > On 12/08/2010 04:36 PM, Joey Lee wrote: > > > Dear all expert, > > > > > > Hi, m... I just google the SATA ODD zero power support and found Henry > > > already contribute the patch: > > > > > > http://kerneltrap.org/mailarchive/linux-scsi/2010/6/25/6885558 > > > > > > And, after first round review, > > > The second version is here: > > > http://www.spinics.net/lists/linux-scsi/msg44925.html > > > > > > But, I didn't see this patch merged in kernel maintain, does there have > > > any problem with this patch? or actually the patch already in queue > > > waiting to merge to mainline? > > > > > > I appreciate if can have any comment to me. > > > > IIRC, at the time, the problem was that nobody had the hardware and > > the implementation was solely based on the specification only. I > > didn't want it to go in without any actual testing, so it was put on > > hold for the time being. Do you have access to a device with zsero > > power support? If so, are you willing to test the implementation? > > > > Got it! > I will do the testing if I get hardware can support this function. > I received a AMD notebook, there have _PS3 method in DSDT table. After test, your SATA ODD zero power patch works to me. The /dev/sr0 was removed when there have no media in tray, patch set ODD power to zero. But I have a bit questions: - I suggest add the kernel config check in drivers/scsi/sr.c like the following, it can avoid compiler error when we disable BLK_DEV_SR_ZERO_POWER: +#ifdef CONFIG_BLK_DEV_SR_ZERO_POWER + cd->type = buffer[n + 6] >> 5; +#endif > > Hmmm... at the same time, I'm a little bit doubtful about its > > usefulness. How much power does it save? Furthermore, ODDs are often > > I am not sure how many watts can be save, it's need use 2-channel power > meter or NetDAQ to verify. I know how to do that, just need the sample > machine. > - After hardware guys test power consumption by 2 channel power-metter, the patch can save 0.1 - 0.2 W (depend on different ODD hardware) when ODD power set to zero. This number is not high. My question is: What's the different between "ODD Zero power" with "SATA Link Power Management on ODD"? (Sorry for I cann't publish more detail power-metter result because it's from my customer's lab.) > > omitted on mobile devices these days. So, I have a slight reluctance > > against including it but if the implementation is clean enough and > > there is enough benefits it shouldn't be too difficult to overcome. > > Fully understood! > > > Thank's a lot! > Joey Lee The last question is: - This Linux patch's behavior is different with Windows platform: When ODD go to "Zero power" mode, if I want to open tray then I need press ODD's tray button TWICE: The first time is enable ODD power and second time for open the tray. But, on Windows, just need press tray button ONE time, then the tray can be opened. Does it possible modify your patch to enable ODD power then direct open tray? Thank's a lot! Joey Lee -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
