From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stefano Babic Date: Mon, 6 Jul 2020 11:10:15 +0200 Subject: Seemless Boot Splash on iMX-based boards In-Reply-To: References: Message-ID: <1d498d4e-d290-dc46-9ec9-42c70a3f7f4d@denx.de> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de Hi Igor, my two cents from previous experience: On 06.07.20 10:34, Igor Opaniuk wrote: > Hi, > > Does anyone have experience in setting up seamless > boot splash on iMX-based platforms? > > I'm currently trying to do that on iMX7-based board with > 4.9 2.3.x IMX downstream kernel running. > Well, i.MX7 have a chance because it has no GPU. I did this for TI based boards, too. But let me say that it is tricky and it creates big dependencies between U-Boot and kernel. And to get a flicker-free images, the clock setup should be exactly the same between U-Boot and kernel, and this is not often (or never) the same because we need a lot of more features (layers, overlays, ..) in kernel, while we just to need to show something like a logo in U-Boot. With the introduction of DRM, things are more difficult. Take also into account that a small change in kernel can be enough to have a weird transition on the framebuffer, and it is more nasty as to start with a black screen. > I've backported console deferred takeover patch-series for fbcon [1], > which permits the contents of the framebuffer (initialized before in U-Boot) > to stay in place as is till error message is shown > or boot is finished. > > The initial splash is shown in U-Boot(mainline) (mxsfb driver is used > for controller/fb initialization). > > Nevertheless, MXSFB controller every time keeps resetting just after > U-Boot->Linux takeover and fb is cleared (I see a black screen) till > login request shows up. Right. > > Questions: > 1. Did anyone have a chance to work on such setups based on deferred > console "feature"? > 2. Does it make sense at all to continue moving towards with this approach > (we initialize graphics core and show boot splash by firmware/bootloader, > then hand over it to Linux). My personal point of view: it makes much more sense to invest the time to speed up the boot process, and let the kernel to boot in a shorten time. And if this time is short enough, kernel has initialized the framebuffer and can show something. This leads also to the main focus for U-Boot, that should be to start the kernel in the shortest time possible. > Taking into account on-going transition to DRM/KMS in the mainline kernel Fully agree. > and that fact that there is no any mainline compatible way to take over > an initialized graphics core, I assume the only generic solution could be > avoiding showing boot logo This is my position, too, and I do not show logo in U-Boot since some years (ok, since starting from DRM /KMS). And well, with i.MX6 / i.MX8, I do not see a chance without a very big effort, and IMHO it is not worth of it. > at all and do that only from the Linux ( > Plymouth-based etc.) Agree. > > Any comments are welcome. Thanks! > > [1] https://patchwork.kernel.org/patch/10432641/ > Best regards, Stefano -- ===================================================================== DENX Software Engineering GmbH, Managing Director: Wolfgang Denk HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: +49-8142-66989-53 Fax: +49-8142-66989-80 Email: sbabic at denx.de =====================================================================