From mboxrd@z Thu Jan 1 00:00:00 1970 From: thierry.reding@gmail.com (Thierry Reding) Date: Tue, 26 Aug 2014 16:41:26 +0200 Subject: [linux-sunxi] Re: [PATCH 4/4] simplefb: add clock handling code In-Reply-To: <20140826123357.GB22395@skynet.be> References: <20140825133953.GJ4163@ulmo.nvidia.com> <53FB3E7F.4000503@redhat.com> <20140825141600.GA14763@ulmo.nvidia.com> <20140825145854.GA15297@lukather> <20140825150501.GE14763@ulmo.nvidia.com> <20140825150900.GB21020@skynet.be> <20140826075247.GC17263@ulmo> <20140826120258.GA22395@skynet.be> <20140826122112.GC641@ulmo> <20140826123357.GB22395@skynet.be> Message-ID: <20140826144125.GC3027@ulmo> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Tue, Aug 26, 2014 at 02:33:57PM +0200, Luc Verhaegen wrote: > On Tue, Aug 26, 2014 at 02:21:16PM +0200, Thierry Reding wrote: > > On Tue, Aug 26, 2014 at 02:02:58PM +0200, Luc Verhaegen wrote: > > > On Tue, Aug 26, 2014 at 09:52:49AM +0200, Thierry Reding wrote: > > > > On Mon, Aug 25, 2014 at 05:09:00PM +0200, Luc Verhaegen wrote: > > > > > On Mon, Aug 25, 2014 at 05:05:04PM +0200, Thierry Reding wrote: > > > > > > > > > > > > No. simplefb just wants to write to some memory that hardware has been > > > > > > set up to scan out. The platform requires that the clocks be on. > > > > > > > > > > Simplefb also requires that the memory is there and is persistent. Fine > > > > > for discrete graphics cards, fine for rpi where most things are hidden > > > > > from the ARM core anyway, not so fine for anybody else. > > > > > > > > I don't understand. This patch series isn't changing anything about the > > > > memory aspects of the driver yet it's working for you on sunxi, isn't > > > > it? So it can't be all that broken. > > > > > > > > Thierry > > > > > > Oh, i had to go wrestle with UBoot options and reserve 8MB off the top, > > > which the kernel never gets told about. A nice throwback to x86 IGP > > > bioses, a past i had thought i had left behind forgood. > > > > Can you not use the reserved memory code (drivers/of/of_reserved_mem.c > > in the kernel)? I think that's the generally accepted way to do this > > with DT. > > > > Thierry > > It was mentioned to me, and I probably could do that, but this seemed > even more DT wrangling from within u-boot, and it didn't seem finished > yet. Plus, all of this already was way more wrangling than i bargained > for, especially with the promise of "simple"-fb. Then there is the > really awkward way in which one gets to define clocks outside of a > dts/compiler (you've seen the code, right?), i really did not feel like > repeating something like that. It could most probably be turned into fairly generic and reusable code so that others can use it. And it would give you a way of recovering those 8 MiB of memory that you'd otherwise loose. Thierry -------------- next part -------------- A non-text attachment was scrubbed... Name: not available Type: application/pgp-signature Size: 819 bytes Desc: not available URL: