[PATCH 0/3] PCI: pciehp: Do not turn off slot if presence comes up after link
In older PCIe specs, PDS (presence detect) would come up when the "in-band" presence detect pin connected, and would be up before DLLLA (link active). In PCIe 4.0 (as an ECN) and in PCIe 5.0, there is a new bit to show if in-band presence detection can be disabled for the slot, and another bit that disables it--and a recommendation that it should be disabled if it can be. In addition, certain OEMs disable in-band presence detection without implementing these bits. This means it is possible to get a "card present" interrupt after the link is up and the driver is loaded. This causes an erroneous removal of the device driver, followed by an immediate re-probing. This patch set defines these new bits, uses them to disable in-band presence detection if it can be, waits for PDS to go up if in-band presence detection is disabled, and adds a DMI table that will let us know if we should assume in-band presence is disabled on a system. The first two patches in this set come from a patch set that was submitted but not accepted many months ago by Alexandru Gagniuc [1]. The first is unmodified, the second has the commit message and timeout modified. [1] https://patchwork.kernel.org/cover/10909167/ [v3,0/4] PCI: pciehp: Do not turn off slot if presence comes up after link Alexandru Gagniuc (2): PCI: pciehp: Add support for disabling in-band presence PCI: pciehp: Wait for PDS if in-band presence is disabled Stuart Hayes (1): PCI: pciehp: Add dmi table for in-band presence disabled drivers/pci/hotplug/pciehp.h | 1 + drivers/pci/hotplug/pciehp_hpc.c | 45 +++- include/uapi/linux/pci_regs.h| 2 ++ 3 files changed, 47 insertions(+), 1 deletion(-) -- 2.18.1
Re: [PATCH 0/3] PCI: pciehp: Do not turn off slot if presence comes up after link
On Wed, Oct 02, 2019 at 05:13:58PM -0500, Alex G. wrote: > On 10/1/19 11:13 PM, Lukas Wunner wrote: > > On Tue, Oct 01, 2019 at 05:14:16PM -0400, Stuart Hayes wrote: > > > This patch set is based on a patch set [1] submitted many months ago by > > > Alexandru Gagniuc, who is no longer working on it. > > > > I'm not sure if it's appropriate to change the author and > > omit Alex' Signed-off-by. > > Legally Dell owns the patches. I have no objection on my end. >From a kernel community POV, I don't think it matters (in this case) who legally owns the copyright to the contributed code. It's just that we go to great lengths to provide proper attribution even for small contributions (e.g. Tested-by). The benefit to the community is that we know who to cc if that portion of the code is changed again and someone knowledgable should take a look. The benefit to contributors is that they can change jobs and their past contributions are still visible in the git history and attributed to their names. By contrast, if you've worked on closed source code and changed jobs, that work isn't visible to future employers or even yourself, and it may happen that someone else takes credit for your past work without you even knowing about it or being able to stop that. (I've seen it before.) In this case, there should be a S-o-b line for Alex preceding that for Stuart, and the author of the commit should be Alex unless a significant portion of the patch was changed. Thanks, Lukas
Re: [PATCH 0/3] PCI: pciehp: Do not turn off slot if presence comes up after link
On 10/1/19 11:13 PM, Lukas Wunner wrote: On Tue, Oct 01, 2019 at 05:14:16PM -0400, Stuart Hayes wrote: This patch set is based on a patch set [1] submitted many months ago by Alexandru Gagniuc, who is no longer working on it. [1] https://patchwork.kernel.org/cover/10909167/ [v3,0/4] PCI: pciehp: Do not turn off slot if presence comes up after link If I'm not mistaken, these two are identical to Alex' patches, right? PCI: pciehp: Add support for disabling in-band presence PCI: pciehp: Wait for PDS when in-band presence is disabled I'm not sure if it's appropriate to change the author and omit Alex' Signed-off-by. Legally Dell owns the patches. I have no objection on my end. Alex Otherwise I have no objections against this series. Thanks, Lukas
Re: [PATCH 0/3] PCI: pciehp: Do not turn off slot if presence comes up after link
On Tue, Oct 1, 2019 at 11:13 PM Lukas Wunner wrote: > > On Tue, Oct 01, 2019 at 05:14:16PM -0400, Stuart Hayes wrote: > > This patch set is based on a patch set [1] submitted many months ago by > > Alexandru Gagniuc, who is no longer working on it. > > > > [1] https://patchwork.kernel.org/cover/10909167/ > > [v3,0/4] PCI: pciehp: Do not turn off slot if presence comes up after > > link > > If I'm not mistaken, these two are identical to Alex' patches, right? > > PCI: pciehp: Add support for disabling in-band presence > PCI: pciehp: Wait for PDS when in-band presence is disabled > > I'm not sure if it's appropriate to change the author and > omit Alex' Signed-off-by. > > Otherwise I have no objections against this series. > > Thanks, > > Lukas Thanks! The first patch is identical to the one Alex submitted, and the second is nearly so... they both basically his work. I wasn't sure what proper etiquette was--I was thinking the signed-off-by was taking responsibility that the patch was ok (functional, not copyrighted by someone else, etc) rather than giving credit, but he definitely deserves credit for them. I'm happy to add a signed-off-by for Alex on the first two and resubmit if he doesn't object.
Re: [PATCH 0/3] PCI: pciehp: Do not turn off slot if presence comes up after link
On Tue, Oct 01, 2019 at 05:14:16PM -0400, Stuart Hayes wrote: > This patch set is based on a patch set [1] submitted many months ago by > Alexandru Gagniuc, who is no longer working on it. > > [1] https://patchwork.kernel.org/cover/10909167/ > [v3,0/4] PCI: pciehp: Do not turn off slot if presence comes up after link If I'm not mistaken, these two are identical to Alex' patches, right? PCI: pciehp: Add support for disabling in-band presence PCI: pciehp: Wait for PDS when in-band presence is disabled I'm not sure if it's appropriate to change the author and omit Alex' Signed-off-by. Otherwise I have no objections against this series. Thanks, Lukas
[PATCH 0/3] PCI: pciehp: Do not turn off slot if presence comes up after link
In older PCIe specs, PDS (presence detect) would come up when the "in-band" presence detect pin connected, and would be up before DLLLA (link active). In PCIe 4.0 (as an ECN) and in PCIe 5.0, there is a new bit to show if in-band presence detection can be disabled for the slot, and another bit that disables it--and a recommendation that it should be disabled if it can be. In addition, certain OEMs disable in-band presence detection without implementing these bits. This means it is possible to get a "card present" interrupt after the link is up and the driver is loaded. This causes an erroneous removal of the device driver, followed by an immediate re-probing. This patch set defines these new bits, uses them to disable in-band presence detection if it can be, waits for PDS to go up if in-band presence detection is disabled, and adds a DMI table that will let us know if we should assume in-band presence is disabled on a system. This patch set is based on a patch set [1] submitted many months ago by Alexandru Gagniuc, who is no longer working on it. [1] https://patchwork.kernel.org/cover/10909167/ [v3,0/4] PCI: pciehp: Do not turn off slot if presence comes up after link Stuart Hayes (3): PCI: pciehp: Add support for disabling in-band presence PCI: pciehp: Wait for PDS when in-band presence is disabled PCI: pciehp: Add dmi table for systems with in-band presence disabled drivers/pci/hotplug/pciehp.h | 1 + drivers/pci/hotplug/pciehp_hpc.c | 45 +++- include/uapi/linux/pci_regs.h| 2 ++ 3 files changed, 47 insertions(+), 1 deletion(-) -- 2.18.1
