Date: Fri, 24 Oct 2025 10:12:30 +0000 From: "Poul-Henning Kamp" <phk@phk.freebsd.dk> To: Konstantin Belousov <kostikbel@gmail.com> Cc: src-committers@freebsd.org, dev-commits-src-all@freebsd.org, dev-commits-src-main@freebsd.org Subject: Re: git: 2612f1b8649b - main - deadfs: Return ENXIO instead of EIO when the device is gone. Message-ID: <202510241012.59OACUDA002781@critter.freebsd.dk> In-Reply-To: <aPs27Dc_w10t3ENH@kib.kiev.ua> References: <202510240741.59O7fBAe041995@gitrepo.freebsd.org> <aPs27Dc_w10t3ENH@kib.kiev.ua>
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-------- Konstantin Belousov writes: > On Fri, Oct 24, 2025 at 07:41:11AM +0000, Poul-Henning Kamp wrote: > > Something changed recently, and while testing this fix, I noticed > Nothing changed WRT code, it is just a race that causes the behavior. That is why I wrote "something", because I agree that it is not code in our tree which has changed. > > that drm-kmod-66/i915kms may be the condition which trigger > > the different code-path. It worries me if loading drm-kmod-66/i915kms can cause this kind of change of behaviour. Even with the fix, I see 2-4 read(2) operations return EIO before the ENXIO manifests. The only hypothesis I have, is that something in DRM-world hogs some kind of HW resource, but I do not have time (nor drm-skillz) to look into that this morning, and I wanted to get the ENXIO fix in for RELENG-15 purposes[1]. I'm also seeing two other "hmm, that's odd" things on -current these days, but they are very specialized so I do not think they should hold up 15: A) When using a GreazeWeazle USB device, the USB connection will get stuck. B) When using a Professional Canon document scanner, the USB connection will get stuck even before the first page is been received. When I next get a chance, I am going to retry both of those scenarios without loading drm-kmod-66/i915kms, to see if makes any difference. Poul-Henning [1]: As I remarked to re@: Measured in years, that is probably the oldest bug I have ever fixed in FreeBSD: According to dds' amazing UNIX history it goes back to 4.4BSD, which means it's probably John Heidemann's mistake. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk@FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence.home | help
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