On Wed, 2020-10-28 at 15:04 -0700, Brian Norris wrote: > On Wed, Oct 28, 2020 at 2:56 PM Tsuchiya Yuto <kitakar@xxxxxxxxx> wrote: > > > > To make the ps_mode (power_save) control easier, this commit adds a new > > module parameter allow_ps_mode and set it false (disallowed) by default. > > This sounds like a bad idea, as it breaks all the existing users who > expect this feature to be allowed. Seems like you should flip the > defaults. Without some better justification, NACK. Thanks for the review! I wanted to open a discussion widely and wanted to ask from the upstream developers the direction of how this stability issue should be resolved. I added the link to the Bugzilla in the cover-letter (that should have arrived on the mailing list now), but I should have added this to every commit as well: BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=109681 This stability issue exists for a long time. I also submitted there the required kernel log and device_dump more than three months ago. However, unfortunately, it's not fixed yet. So, I have to send a series like this. If we know that the power_save feature is broken (on some devices), I think it should be fixed in either firmware or driver for the affected devices. It makes no sense to keep enabling the broken features by default. Because userspace tools sometimes try to enable power_save anyway regardless of default driver settings (expecting it's not broken, but in fact it's broken), the module parameter like this is required in addition to the first patch of this series. The commit 8298383c2cd5 ("ath9k: Do not support PowerSave by default") also does the same thing for this purpose. On the other hand, I agree that I don't want to break the existing users. As you mentioned in the reply to the first patch, I can set the default value of this parameter depending on the chip id (88W8897) or DMI matching. > Also, I can't find the other 2 patches in this alleged series. Maybe > they're still making it through the mailing lists and archives. Yes, there seems to be a problem with the mailing list at the time. All the other patches I sent have arrived by now. > Brian > > > When this parameter is set to false, changing the power_save mode will > > be disallowed like the following: > > > > $ sudo iw dev mlan0 set power_save on > > command failed: Operation not permitted (-1) > > > > Signed-off-by: Tsuchiya Yuto <kitakar@xxxxxxxxx>
