From mboxrd@z Thu Jan 1 00:00:00 1970 From: boris.brezillon@bootlin.com (Boris Brezillon) Date: Wed, 28 Mar 2018 14:25:12 +0200 Subject: [PATCH] drm/atmel-hlcdc: add command line option to specify preferred depth In-Reply-To: <20180328122236.GF14155@phenom.ffwll.local> References: <20180326073502.19259-1-peda@axentia.se> <20180328093454.4149fa3b@bbrezillon> <20180328122236.GF14155@phenom.ffwll.local> Message-ID: <20180328142512.14f8c502@bbrezillon> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Wed, 28 Mar 2018 14:22:36 +0200 Daniel Vetter wrote: > On Wed, Mar 28, 2018 at 09:34:54AM +0200, Boris Brezillon wrote: > > Hi Peter, > > > > On Mon, 26 Mar 2018 09:35:02 +0200 > > Peter Rosin wrote: > > > > > I have an sama5d31-based system with 64MB of memory and a 1920x1080 > > > LVDS display wired for 16-bpp. When I enable legacy fbdev support, > > > the contiguous memory allocator invariably fails with the order-11 > > > allocation for a 1920x1080 at 24-bpp buffer (~6MB). But this HW can never > > > make any good use of RGB888, so that is a wasted attempt anyway that > > > would also waste precious memory should it succeed. > > > > > > Sure, I could rewrite user-space to go directly to KMS etc, and that > > > makes the (attempted) order-11 allocation go away, replacing it with > > > one order-10 allocation per application restart for a 1920x1080 at 16-bpp > > > buffer (<4MB). But after a few restarts, order-10 allocations start to > > > fail as well, which is only to be expected AFAIU. > > > > > > So, I'd rather not change user-space (which was originally written > > > to target a smaller display) so that I at the same time get the > > > benefit of an early pre-allocated fbdev frame-buffer that can be > > > reused over and over. But to do that I need to tell the driver that > > > 16-bpp is the preferred depth. Add a module parameter to do just that. > > > > > > Signed-off-by: Peter Rosin > > > --- > > > drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_dc.c | 18 +++++++++++++++++- > > > 1 file changed, 17 insertions(+), 1 deletion(-) > > > > > > I found some inspiration regarding naming and implementation here: > > > https://patchwork.kernel.org/patch/9848631/ > > > > > > I have found no feedback on that patch though, which makes me wonder if > > > I'm perhaps barking up the wronig tree? > > > > Hm, isn't that something you can already overload with the video= > > parameter? > > > > video=:[-] > > > > AFAIR, encodes the color depth, so what is the benefit of adding > > this new property to overload the default depth? > > > > Maybe I'm wrong and the default depth param is actually useful, but in > > this case we should probably make it generic since other drivers seems > > to need it too, and we might want to attach it to a specific display > > engine instance. > > I think for the drm's fbdev emulation we ignore the bpp ... Nope, it's already parsed [1]. [1]https://elixir.bootlin.com/linux/v4.16-rc3/source/drivers/gpu/drm/drm_fb_helper.c#L1812 -- Boris Brezillon, Bootlin (formerly Free Electrons) Embedded Linux and Kernel engineering https://bootlin.com From mboxrd@z Thu Jan 1 00:00:00 1970 From: Boris Brezillon Subject: Re: [PATCH] drm/atmel-hlcdc: add command line option to specify preferred depth Date: Wed, 28 Mar 2018 14:25:12 +0200 Message-ID: <20180328142512.14f8c502@bbrezillon> References: <20180326073502.19259-1-peda@axentia.se> <20180328093454.4149fa3b@bbrezillon> <20180328122236.GF14155@phenom.ffwll.local> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Return-path: Received: from mail.bootlin.com (mail.bootlin.com [62.4.15.54]) by gabe.freedesktop.org (Postfix) with ESMTP id 16C7E89330 for ; Wed, 28 Mar 2018 12:25:15 +0000 (UTC) In-Reply-To: <20180328122236.GF14155@phenom.ffwll.local> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" To: Daniel Vetter Cc: Egbert Eich , Boris Brezillon , Alexandre Belloni , David Airlie , linux-kernel@vger.kernel.org, Nicolas Ferre , dri-devel@lists.freedesktop.org, Takashi Iwai , Peter Rosin , linux-arm-kernel@lists.infradead.org List-Id: dri-devel@lists.freedesktop.org T24gV2VkLCAyOCBNYXIgMjAxOCAxNDoyMjozNiArMDIwMApEYW5pZWwgVmV0dGVyIDxkYW5pZWxA ZmZ3bGwuY2g+IHdyb3RlOgoKPiBPbiBXZWQsIE1hciAyOCwgMjAxOCBhdCAwOTozNDo1NEFNICsw MjAwLCBCb3JpcyBCcmV6aWxsb24gd3JvdGU6Cj4gPiBIaSBQZXRlciwKPiA+IAo+ID4gT24gTW9u LCAyNiBNYXIgMjAxOCAwOTozNTowMiArMDIwMAo+ID4gUGV0ZXIgUm9zaW4gPHBlZGFAYXhlbnRp YS5zZT4gd3JvdGU6Cj4gPiAgIAo+ID4gPiBJIGhhdmUgYW4gc2FtYTVkMzEtYmFzZWQgc3lzdGVt IHdpdGggNjRNQiBvZiBtZW1vcnkgYW5kIGEgMTkyMHgxMDgwCj4gPiA+IExWRFMgZGlzcGxheSB3 aXJlZCBmb3IgMTYtYnBwLiBXaGVuIEkgZW5hYmxlIGxlZ2FjeSBmYmRldiBzdXBwb3J0LAo+ID4g PiB0aGUgY29udGlndW91cyBtZW1vcnkgYWxsb2NhdG9yIGludmFyaWFibHkgZmFpbHMgd2l0aCB0 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ZwpodHRwczovL2Jvb3RsaW4uY29tCl9fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19f X19fX19fX19fX19fCmRyaS1kZXZlbCBtYWlsaW5nIGxpc3QKZHJpLWRldmVsQGxpc3RzLmZyZWVk ZXNrdG9wLm9yZwpodHRwczovL2xpc3RzLmZyZWVkZXNrdG9wLm9yZy9tYWlsbWFuL2xpc3RpbmZv L2RyaS1kZXZlbAo= From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752587AbeC1MZQ (ORCPT ); Wed, 28 Mar 2018 08:25:16 -0400 Received: from mail.bootlin.com ([62.4.15.54]:55351 "EHLO mail.bootlin.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752154AbeC1MZP (ORCPT ); Wed, 28 Mar 2018 08:25:15 -0400 Date: Wed, 28 Mar 2018 14:25:12 +0200 From: Boris Brezillon To: Daniel Vetter Cc: Peter Rosin , Egbert Eich , Boris Brezillon , Alexandre Belloni , David Airlie , Nicolas Ferre , Takashi Iwai , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH] drm/atmel-hlcdc: add command line option to specify preferred depth Message-ID: <20180328142512.14f8c502@bbrezillon> In-Reply-To: <20180328122236.GF14155@phenom.ffwll.local> References: <20180326073502.19259-1-peda@axentia.se> <20180328093454.4149fa3b@bbrezillon> <20180328122236.GF14155@phenom.ffwll.local> X-Mailer: Claws Mail 3.15.0-dirty (GTK+ 2.24.31; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 28 Mar 2018 14:22:36 +0200 Daniel Vetter wrote: > On Wed, Mar 28, 2018 at 09:34:54AM +0200, Boris Brezillon wrote: > > Hi Peter, > > > > On Mon, 26 Mar 2018 09:35:02 +0200 > > Peter Rosin wrote: > > > > > I have an sama5d31-based system with 64MB of memory and a 1920x1080 > > > LVDS display wired for 16-bpp. When I enable legacy fbdev support, > > > the contiguous memory allocator invariably fails with the order-11 > > > allocation for a 1920x1080@24-bpp buffer (~6MB). But this HW can never > > > make any good use of RGB888, so that is a wasted attempt anyway that > > > would also waste precious memory should it succeed. > > > > > > Sure, I could rewrite user-space to go directly to KMS etc, and that > > > makes the (attempted) order-11 allocation go away, replacing it with > > > one order-10 allocation per application restart for a 1920x1080@16-bpp > > > buffer (<4MB). But after a few restarts, order-10 allocations start to > > > fail as well, which is only to be expected AFAIU. > > > > > > So, I'd rather not change user-space (which was originally written > > > to target a smaller display) so that I at the same time get the > > > benefit of an early pre-allocated fbdev frame-buffer that can be > > > reused over and over. But to do that I need to tell the driver that > > > 16-bpp is the preferred depth. Add a module parameter to do just that. > > > > > > Signed-off-by: Peter Rosin > > > --- > > > drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_dc.c | 18 +++++++++++++++++- > > > 1 file changed, 17 insertions(+), 1 deletion(-) > > > > > > I found some inspiration regarding naming and implementation here: > > > https://patchwork.kernel.org/patch/9848631/ > > > > > > I have found no feedback on that patch though, which makes me wonder if > > > I'm perhaps barking up the wronig tree? > > > > Hm, isn't that something you can already overload with the video= > > parameter? > > > > video=:[-] > > > > AFAIR, encodes the color depth, so what is the benefit of adding > > this new property to overload the default depth? > > > > Maybe I'm wrong and the default depth param is actually useful, but in > > this case we should probably make it generic since other drivers seems > > to need it too, and we might want to attach it to a specific display > > engine instance. > > I think for the drm's fbdev emulation we ignore the bpp ... Nope, it's already parsed [1]. [1]https://elixir.bootlin.com/linux/v4.16-rc3/source/drivers/gpu/drm/drm_fb_helper.c#L1812 -- Boris Brezillon, Bootlin (formerly Free Electrons) Embedded Linux and Kernel engineering https://bootlin.com