Thanks Dianne, That is really excellent insider's tip we need to know about.
I will now be using v.2.6.32 for FPGA's linux distribution On Oct 4, 12:07 pm, Arindam Roy <rarin...@gmail.com> wrote: > Also Diane, I think it wouldn't be a good idea, not to use the same kernel > as the android git, as that undoes the effort that your team has spent, and > leads to duplication. > Another point is, if one is using the same kernel, and reports any issue to > this list, then all the others can easily help. Otherwise these subtle > differences as you mentioned may inhibit the reproduction of the same issue > for different developers. > Thanks, > Arindam > > On Mon, Oct 4, 2010 at 10:27 AM, Dianne Hackborn <hack...@android.com>wrote: > > > Here's a story illustrating why I would recommend sticking with the same > > version of the kernel that a particular version of Android was developed > > against (at least initially). > > > Froyo was developed against 2.6.32. We are currently developing against > > 2.6.35 post-Froyo. > > > I and many others have just gone through literally *weeks* of effort trying > > to fix some problems in the development code, causing everything from > > individual apps ANRing with no clear reason, through the entire system just > > stopping for 30s or more, to the entire kernel crashing. > > > It turns out that a lot of this (though not all) is due to some issues in > > the 2.6.35 kernel with what happens when running threads switch between > > cgroups. (This is something that Android does a lot, which probably nobody > > else using Linux does.) > > > So in theory, yes you can say that user space is independent from the > > kernel, and you won't have a problem switching to a different kernel. In > > practice, however, there are all kinds of subtle interactions that can come > > up due to bugs in user space or the kernel or not even bugs but just > > differences in behavior that when put together cause serious problems. > > > When you start out, you really want to change as little as possible. The > > faster you can get to a stable running system, the easier a time you will > > have in the future when things fall apart (as they inevitably will). If you > > can know that at point A things were fine, that greatly narrows down what > > you need to dig into to figure out what has gone wrong at point B. > > > On Wed, Sep 22, 2010 at 6:59 PM, markgross <mark.gr...@intel.com> wrote: > > >> Glibc has a dependency on the 2.6 kenrel tree too, but that doesn't > >> mean there is a dependency between on 2.6 kernel and another for > >> propper user mode support. > > >> Yes I have seen those files. They define the sys call ABI that bionic > >> uses. There is nothing magic or tightly coupled to the specific > >> kernel version other than you need a newer kernel than 2.4 to satisfy > >> the assupmtions therein. > > >> All thats important is the kernel expose the kernel ABI assumed by the > >> user mode. So far that is only: > >> 2.6 erra sys_calls for the android libc (bionic) > >> binder > >> wake lock > >> ashmem > >> early (consol) suspend > >> logger > > >> (i think thats all, asside from stuff thats already in the upstream > >> kernel tree like frame buffer, audio, network, input, and a few other > >> things you need to be sure to have enabled in your kernel config.) > > >> --mark > > >> On Sep 22, 10:38 am, Vikram <vikrampand...@gmail.com> wrote: > >> > hi Mark > > >> > Why do you say there is no relationship between userspace and the > >> > kernel version? > > >> > Did you check: > >> > Kernel: > >> > include/linux/.... > > >> > and > > >> > Android 2.2: > >> > bionic/libc/kernel/common/linux/..... > > >> > There are same header files shared between kernel and the filesystem. > >> > thus introducing a dependency between filesystem and the kernel > >> > version. > > >> > Some script is run on kernel headers to generate the filesystem > >> > headers and i think Android team must be doing it once every pastry > >> > release. > > >> > See example header: > >>http://android.git.kernel.org/?p=platform/bionic.git;a=blob;f=libc/ke... > >> > 1 / > > >> **************************************************************************** > >> > 2 > > >> **************************************************************************** > >> > 3 *** > >> > 4 *** This header was automatically generated from a Linux > >> > kernel header > >> > 5 *** of the same name, to make information necessary for > >> > userspace to > >> > 6 *** call into the kernel available to libc. It contains only > >> > constants, > >> > 7 *** structures, and macros generated from the original header, > >> > and thus, > >> > 8 *** contains no copyrightable information. > >> > 9 *** > >> > 10 > > >> **************************************************************************** > >> > 11 > > >> ****************************************************************************/ > > >> > On Aug 6, 8:03 am, markgross <mark.gr...@intel.com> wrote:> I am > >> booting Froyo (and Eclair) on a 2.6.31 and 2.6.34 kernels today, > >> > > I would bet money you could boot them on a 2.6.29 kernel as well. > > >> > > You just need the critical kenrel patches for it to work. i.e. > >> > > binder, asmem, wakelocks, logger, and one or two more, you can easily > >> > > rebase out of the refrence kernel trees google puts up. > > >> > > --mgross > > >> > > On Aug 4, 3:17 pm, hedwin <hedwin.kon...@gmail.com> wrote: > > >> > > > Hi, > > >> > > > Which kernel version do I need to use for Froyo? > >> > > > I tried the same version as used for Eclair (2.6.32) but that does > >> > > > work for Froyo. > > >> > > > Hedwin > > >> -- > >> unsubscribe: > >> android-kernel+unsubscr...@googlegroups.com<android-kernel%2bunsubscr...@googlegroups.com> > >> website:http://groups.google.com/group/android-kernel > > > -- > > Dianne Hackborn > > Android framework engineer > > hack...@android.com > > > Note: please don't send private questions to me, as I don't have time to > > provide private support, and so won't reply to such e-mails. All such > > questions should be posted on public forums, where I and others can see and > > answer them. > > > -- > > unsubscribe: > > android-kernel+unsubscr...@googlegroups.com<android-kernel%2bunsubscr...@googlegroups.com> > > website:http://groups.google.com/group/android-kernel > > -- unsubscribe: android-kernel+unsubscr...@googlegroups.com website: http://groups.google.com/group/android-kernel
