Am 08.11.2023 um 23:26 hat Niklas Cassel geschrieben: > From: Niklas Cassel <niklas.cas...@wdc.com> > > Legacy software contains a standard mechanism for generating a reset to a > Serial ATA device - setting the SRST (software reset) bit in the Device > Control register. > > Serial ATA has a more robust mechanism called COMRESET, also referred to > as port reset. A port reset is the preferred mechanism for error > recovery and should be used in place of software reset. > > Commit e2a5d9b3d9c3 ("hw/ide/ahci: simplify and document PxCI handling") > improved the handling of PxCI, such that PxCI gets cleared after handling > a non-NCQ, or NCQ command (instead of incorrectly clearing PxCI after > receiving anything - even a FIS that failed to parse, which should NOT > clear PxCI, so that you can see which command slot that caused an error). > > However, simply clearing PxCI after a non-NCQ, or NCQ command, is not > enough, we also need to clear PxCI when receiving a SRST in the Device > Control register. > > A legacy software reset is performed by the host sending two H2D FISes, > the first H2D FIS asserts SRST, and the second H2D FIS deasserts SRST. > > The first H2D FIS will not get a D2H reply, and requires the FIS to have > the C bit set to one, such that the HBA itself will clear the bit in PxCI. > > The second H2D FIS will get a D2H reply once the diagnostic is completed. > The clearing of the bit in PxCI for this command should ideally be done > in ahci_init_d2h() (if it was a legacy software reset that caused the > reset (a COMRESET does not use a command slot)). However, since the reset > value for PxCI is 0, modify ahci_reset_port() to actually clear PxCI to 0, > that way we can avoid complex logic in ahci_init_d2h(). > > This fixes an issue for FreeBSD where the device would fail to reset. > The problem was not noticed in Linux, because Linux uses a COMRESET > instead of a legacy software reset by default. > > Fixes: e2a5d9b3d9c3 ("hw/ide/ahci: simplify and document PxCI handling") > Reported-by: Marcin Juszkiewicz <marcin.juszkiew...@linaro.org> > Signed-off-by: Niklas Cassel <niklas.cas...@wdc.com>
Thanks, applied to the block branch. Kevin