Hello, all. This is the first take of hotplug polling patchset. As the name implies, this patchset implements hotplug by polling. libata core layer implements hp-poll infrastructure. It interacts with LLDs with three callbacks - hp_poll_activate(), hp_poll_deactivate() and hp_poll(). libata core layer is responsible for activating and deactivating at the right time, invoking the poll callback periodically while activated, and generate hotplug event when poll callback indicates something has happened. hp-poll is used for the following cases. * To detect hotplug events on frozen ports after reset fails such that replacing or replugging the failing device make libata automatically retry the port. * To detect hotplug events on LLDs without hotplug interrupt. The following drivers are converted to use hp-poll on failed ports. * ahci * sata_nv (nf2 and ck804 only) [untested] * sata_sil * sata_sil24 The following drivers are converted to use hp-poll for hotplug * sata_nv (generic) [untested] * sata_sis [untested] * sata_svw [untested] * sata_uli [untested] * sata_via * sata_vsc [untested] There are three variants of sata_std_poll() - regular, port-exclusive and host_set-exclusive. port-exclusive skips polling if command is in progress to the port. host_set-exclusive skips polling if one or more commands are in progress to any port in the host_set. This is because some controllers lock up if SCR regs are accessed while command is in progress. Well, the port-exclusive case is dumb but understandable; however, sata_via (vt8237) takes it to the next level and may lock up if any available port in the host_set is active when a SCR reg is accessed, so it needs host_set-exclusive version. It took me two days of boredom to figure out that things can be made THAT dumb. Their new AHCI controller also seems to require host_set-wide EH ops to recover from errors. Well, I guess they consider requiring host_set-wide ops a feature or something. :-( Note that this means that the current libata EH may lock up the whole machine on vt8237 if EH occurs at a bad time. Currently, all 'untested' LLDs are using the regular version and some of them might need to use a dumber version. So, we need some testing here. This patchset is against upstream (2154cfa6ba560401d25f6cc083fe3fb996cbb571) + add-ap-pflags [1] + fix-ehc_i_action-setting-in-ata_eh_autopsy [2] + cosmetic-replace-ap_lock [3] + new PM patchset [4] This patchset is also available in the following git tree. http://htj.dyndns.org/git/?p=libata-tj.git;a=shortlog;h=hp-poll git://htj.dyndns.org/libata-tj hp-poll Thanks. -- tejun [1] http://article.gmane.org/gmane.linux.ide/11717 [2] http://article.gmane.org/gmane.linux.ide/11801 [3] http://article.gmane.org/gmane.linux.ide/11802 [4] http://article.gmane.org/gmane.linux.ide/11816 - : 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
