Hi David, all, > -----Original Message----- > From: David Miller [mailto:davem@xxxxxxxxxxxxx] > Sent: Monday, January 30, 2017 2:16 AM > To: Alexey.Brodkin@xxxxxxxxxxxx > Cc: netdev@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; > peppe.cavallaro@xxxxxx; fabrice.gasnier@xxxxxx; manabian@xxxxxxxxx; > preid@xxxxxxxxxxxxxxxxx; alexandre.torgue@xxxxxxxxx; > Vineet.Gupta1@xxxxxxxxxxxx > Subject: Re: [PATCH] stmmac: Discard masked flags in interrupt status > register > > From: Alexey Brodkin <Alexey.Brodkin@xxxxxxxxxxxx> > Date: Fri, 27 Jan 2017 15:24:43 +0300 > > > DW GMAC databook says the following about bits in "Register 15 > > (Interrupt Mask Register)": > > --------------------------->8------------------------- > > When set, this bit __disables_the_assertion_of_the_interrupt_signal__ > > because of the setting of XXX bit in Register 14 (Interrupt Status > > Register). > > --------------------------->8------------------------- > > > > In fact even if we mask one bit in the mask register it doesn't > > prevent corresponding bit to appear in the status register, it only > > disables interrupt generation for corresponding event. > > > > But currently we expect a bit different behavior: status bits to be in > > sync with their masks, i.e. if mask for bit A is set in the mask > > register then bit A won't appear in the interrupt status register. > > > > This was proven to be incorrect assumption, see discussion here [1]. > > That misunderstanding causes unexpected behaviour of the GMAC, for > > example we were happy enough to just see bogus messages about link > > state changes. > > > > So from now on we'll be only checking bits that really may trigger an > > interrupt. > > > > [1] https://lkml.org/lkml/2016/11/3/413 > > > > Signed-off-by: Alexey Brodkin <abrodkin@xxxxxxxxxxxx> > > This looks good, applied, thanks. May we have that one back-ported to stable branches starting from 4.8.x? That issue started to appear due to a change from pr_debug() to pr_info() in commit 70523e639bf8 ("drivers: net: stmmac: reworking the PCS code."). -Alexey -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html