Messages in this thread |  | | Date | Fri, 04 Jan 2013 14:36:09 +0100 | From | Alexander Holler <> | Subject | Re: [PATCH] fb: Rework locking to fix lock ordering on takeover |
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Am 04.01.2013 14:25, schrieb Alan Cox: > On Fri, 04 Jan 2013 13:50:37 +0100 > Alexander Holler <holler@ahsoftware.de> wrote: > >> Am 28.12.2012 13:40, schrieb Borislav Petkov: >>> On Fri, Dec 28, 2012 at 07:50:27PM +0800, Shawn Guo wrote: >>>> +1 >>>> >>>> http://thread.gmane.org/gmane.linux.kernel/1413953/focus=1415070 >>> >>> Cool, works fine here too. Is Linus on CC? (/me checks.. ) Yes he is, >>> good. >>> >>> Linus, Alan's patch works at least in 2 cases, you might consider >>> picking it up directly since the fb maintainer is absent, reportedly. >> >> >> Btw. I think all the usb-fb's (udlfb, smscufx and udl) are broken, at >> least on ARM(v5). When I have linked in udlfb the following happens on >> boot (with an attached USB-LCD and with or without the "Rework locking >> patch): > > They are broken if used as the system console (has been known for years).
Ah. Thats why I didn't see it before. Usually I've used the serial as system console. So thats why it worked before. ;)
> Perhaps your x86 test has the system console still on another device ?
Exactly thats the case. Thanks for pointing it out.
> For the udl layer it shouldn't matter as Dave Airlie wrote a DRM driver > for udl which obsoletes the old fb layer one and works much better > (although the error handling is still totally broken and leaks like a > sieve if it fails) > > Fixing the console isn't that difficult - you just need to make your > device queue the console I/O to a worker thread of some kind. We don't
That is what I wanted to try next. ;)
> want to do that by default because we want to get the messages out > reliably and immediately on saner hardware. Given there are several > such cases a general helper and a console "I am crap" flag might be better > than hacking each driver.
All those drivers look very similiar. I will see if I'm successfull in writing such an IamCrapHelper. Might need some time, but I will post a patch for review, if I've done and tested it. I'm only using the USB-LCD on occasion, so it doesn't have high priority for me because I don't really need it.
Thanks for the hints.
Regards,
Alexander
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