[Ksummit-2011-discuss] Topic suggestions for KS/2011

[Mauro Carvalho Chehab]

I have two topic suggestions for KS/2011.


1) Title: Hardware Event Report Mechanism

This is somewhat somewhat related to Kay Sievers proposal for a better way to report
errors to userspace, instead of the plain-old printk way.

Abstract: Several ways to report hardware errors were developed in the past, including
EDAC and MCE. Each one has its merits, but both are incomplete. Also, MCE is x86
architecture dependent, and requires an external userspace program to translate
machine-dependent magic numbers into something meaningful. The target is to replace
or integrate both mechanisms into a consistent kernelspace-userspace interface,
using perf support.

Suggested participants: me, Tony Luck and Borislav Petkov

2) Title: Driver-wide resource locking

Abstract: Some new devices found at the market have really complex hardware
designs. We're currently seeing device drivers under the media tree that needs
to support several different userspace API's, and on several cases, with some
IP blocks shared by more than one driver. So, the very same device has 3 of 4
I2C buses, analog and digital audio input/output, video stream input/output,
Remote Controller and digital TV output. Locking IP resources on such hardware
are a complex task. For example, on some devices, the audio capture uses the
standard USB Audio Class, being handled by the snd-usb-audio, while the video
stream is handled by a completely independent driver. However, if such device
is being used by the DVB API, the V4L API access should be disabled, and the
access via ALSA API will be internally disabled at the hardware level. So,
the alsa driver should be returning -EBUSY.

As these drivers are seeing by more than one subsystem, we probably need to
work on some resource reservation mechanism at drivers core level.

We'll be discussing about this subject during the USB mini-summit next week,
but, as this issue is bus-agnostic, I'd like to discuss the possible 
alternatives for such problem on a broader forum, in order to see if this
is a common problem, and address it properly.

Thanks,
Mauro