Re: [PATCH v4 2/2] usb: dwc2: host: Clear interrupts before handling them
Felipe, On Fri, Nov 20, 2015 at 7:40 AM, Felipe Balbiwrote: > > Hi, > > Douglas Anderson writes: >> In general it is wise to clear interrupts before processing them. If >> you don't do that, you can get: >> 1. Interrupt happens >> 2. You look at system state and process interrupt >> 3. A new interrupt happens >> 4. You clear interrupt without processing it. >> >> This patch was actually a first attempt to fix missing device insertions >> as described in (usb: dwc2: host: Fix missing device insertions) and it >> did solve some of the signal bouncing problems but not all of >> them (which is why I submitted the other patch). Specifically, this >> patch itself would sometimes change: >> 1. hardware sees connect >> 2. hardware sees disconnect >> 3. hardware sees connect >> 4. dwc2_port_intr() - clears connect interrupt >> 5. dwc2_handle_common_intr() - calls dwc2_hcd_disconnect() >> >> ...to: >> 1. hardware sees connect >> 2. hardware sees disconnect >> 3. dwc2_port_intr() - clears connect interrupt >> 4. hardware sees connect >> 5. dwc2_handle_common_intr() - calls dwc2_hcd_disconnect() >> >> ...but with different timing then sometimes we'd still miss cable >> insertions. >> >> In any case, though this patch doesn't fix any (known) problems, it >> still seems wise as a general policy to clear interrupt before handling >> them. >> >> Note that for dwc2_handle_usb_port_intr(), instead of moving the clear >> of PRTINT to the beginning of the function we remove it completely. The >> only way to clear PRTINT is to clear the sources that set it in the >> first place. >> >> Signed-off-by: Douglas Anderson >> Acked-by: John Youn >> Tested-by: John Youn > > $ patch -p1 --dry-run < patch.diff > checking file drivers/usb/dwc2/core_intr.c > checking file drivers/usb/dwc2/hcd_intr.c > Hunk #4 FAILED at 365. > Hunk #5 succeeded at 388 (offset 11 lines). > 1 out of 5 hunks FAILED > > Care to rebase on top of my testing/next ? No problem. ...though when I did that, I actually found (by code inspection) a bug in the original patch, so I guess it's a good thing it didn't apply... ...and then that led me to another bug that was pre-existing. I'll send up two new patches shortly. I'll remove John's Ack and Tested tags from the patch since it contains a change. It looks like you already landed part 1 of this series (usb: dwc2: host: Fix missing device insertions) so I won't resend that. -Doug -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH v4 2/2] usb: dwc2: host: Clear interrupts before handling them
Hi, Douglas Andersonwrites: > In general it is wise to clear interrupts before processing them. If > you don't do that, you can get: > 1. Interrupt happens > 2. You look at system state and process interrupt > 3. A new interrupt happens > 4. You clear interrupt without processing it. > > This patch was actually a first attempt to fix missing device insertions > as described in (usb: dwc2: host: Fix missing device insertions) and it > did solve some of the signal bouncing problems but not all of > them (which is why I submitted the other patch). Specifically, this > patch itself would sometimes change: > 1. hardware sees connect > 2. hardware sees disconnect > 3. hardware sees connect > 4. dwc2_port_intr() - clears connect interrupt > 5. dwc2_handle_common_intr() - calls dwc2_hcd_disconnect() > > ...to: > 1. hardware sees connect > 2. hardware sees disconnect > 3. dwc2_port_intr() - clears connect interrupt > 4. hardware sees connect > 5. dwc2_handle_common_intr() - calls dwc2_hcd_disconnect() > > ...but with different timing then sometimes we'd still miss cable > insertions. > > In any case, though this patch doesn't fix any (known) problems, it > still seems wise as a general policy to clear interrupt before handling > them. > > Note that for dwc2_handle_usb_port_intr(), instead of moving the clear > of PRTINT to the beginning of the function we remove it completely. The > only way to clear PRTINT is to clear the sources that set it in the > first place. > > Signed-off-by: Douglas Anderson > Acked-by: John Youn > Tested-by: John Youn $ patch -p1 --dry-run < patch.diff checking file drivers/usb/dwc2/core_intr.c checking file drivers/usb/dwc2/hcd_intr.c Hunk #4 FAILED at 365. Hunk #5 succeeded at 388 (offset 11 lines). 1 out of 5 hunks FAILED Care to rebase on top of my testing/next ? -- balbi signature.asc Description: PGP signature
Re: [PATCH v4 2/2] usb: dwc2: host: Clear interrupts before handling them
Hi, On Fri, Nov 20, 2015 at 8:49 AM, Doug Andersonwrote: > Felipe, > > On Fri, Nov 20, 2015 at 7:40 AM, Felipe Balbi wrote: >> >> Hi, >> >> Douglas Anderson writes: >>> In general it is wise to clear interrupts before processing them. If >>> you don't do that, you can get: >>> 1. Interrupt happens >>> 2. You look at system state and process interrupt >>> 3. A new interrupt happens >>> 4. You clear interrupt without processing it. >>> >>> This patch was actually a first attempt to fix missing device insertions >>> as described in (usb: dwc2: host: Fix missing device insertions) and it >>> did solve some of the signal bouncing problems but not all of >>> them (which is why I submitted the other patch). Specifically, this >>> patch itself would sometimes change: >>> 1. hardware sees connect >>> 2. hardware sees disconnect >>> 3. hardware sees connect >>> 4. dwc2_port_intr() - clears connect interrupt >>> 5. dwc2_handle_common_intr() - calls dwc2_hcd_disconnect() >>> >>> ...to: >>> 1. hardware sees connect >>> 2. hardware sees disconnect >>> 3. dwc2_port_intr() - clears connect interrupt >>> 4. hardware sees connect >>> 5. dwc2_handle_common_intr() - calls dwc2_hcd_disconnect() >>> >>> ...but with different timing then sometimes we'd still miss cable >>> insertions. >>> >>> In any case, though this patch doesn't fix any (known) problems, it >>> still seems wise as a general policy to clear interrupt before handling >>> them. >>> >>> Note that for dwc2_handle_usb_port_intr(), instead of moving the clear >>> of PRTINT to the beginning of the function we remove it completely. The >>> only way to clear PRTINT is to clear the sources that set it in the >>> first place. >>> >>> Signed-off-by: Douglas Anderson >>> Acked-by: John Youn >>> Tested-by: John Youn >> >> $ patch -p1 --dry-run < patch.diff >> checking file drivers/usb/dwc2/core_intr.c >> checking file drivers/usb/dwc2/hcd_intr.c >> Hunk #4 FAILED at 365. >> Hunk #5 succeeded at 388 (offset 11 lines). >> 1 out of 5 hunks FAILED >> >> Care to rebase on top of my testing/next ? > > No problem. > > ...though when I did that, I actually found (by code inspection) a bug > in the original patch, so I guess it's a good thing it didn't apply... > ...and then that led me to another bug that was pre-existing. I'll > send up two new patches shortly. I'll remove John's Ack and Tested > tags from the patch since it contains a change. > > It looks like you already landed part 1 of this series (usb: dwc2: > host: Fix missing device insertions) so I won't resend that. Ah, OK. Now I see why nobody found these problems in testing. The code path is completely disabled by all current parameters as checked in to mainline. In any case, it's good to fix. -Doug -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html