From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 68C0EC5DF62 for ; Wed, 26 Jan 2022 02:25:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236268AbiAZCZY (ORCPT ); Tue, 25 Jan 2022 21:25:24 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:32772 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236302AbiAZCZW (ORCPT ); Tue, 25 Jan 2022 21:25:22 -0500 Received: from mail-ua1-x933.google.com (mail-ua1-x933.google.com [IPv6:2607:f8b0:4864:20::933]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 63EE1C06161C; Tue, 25 Jan 2022 18:25:22 -0800 (PST) Received: by mail-ua1-x933.google.com with SMTP id y4so40907161uad.1; Tue, 25 Jan 2022 18:25:22 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc:content-transfer-encoding; bh=Nsd0iFumaY43f2QkfXEIN5y4w31w3uWjtzxOZaSzScA=; b=ajC5QCSvrV8ckjekoyQ030W1UTCPdashc35ExAL7hW6yRDZ3s80VedN+GEg3E1Koq4 596R04YIbjK/maAFGmkmt/4WM7w7oT78VG7U6wSysTvwqBGTTTbF7erIac+yZ3xp7Ivy VTWAktor5HaIGKvQVmOidtZgnTyarGoPoStZWXZNMOqzuB5JA9fWMARTa2JOe/s+fcFH 7rbulBWYC15d4DMGaqpozwAVAhg7MVtbx3wkxLnHkGoExpbUF0kpBNBk1OXDknzFwfab wVQlFGe0M+Nc3HYDIpRr9YusCexe1NUaCjRa9x1iyAbXx0OoDdM4oTDsu7h3rDV64+U0 mxiw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc:content-transfer-encoding; bh=Nsd0iFumaY43f2QkfXEIN5y4w31w3uWjtzxOZaSzScA=; b=zfDJrs5DMO+rqzw3RNn4vg5MY0TyV1A8ZpxfwrTxpoezwSI3wdaZrm6jPX8wBcNiyx /24ytEZh7v9LX7G07NXBPa9KTy+y+yPs86o7fL1x2hA+Lf++sC81HzmQxBNyZYHuJ7cL 8KsjtXHlt6yoyhRHrgOmB1pFWiAZj1JR89y+8RzrRAKNkNwe5jnTp/Q93DxcPNFA0ind JIkki8ykBzGwaF7et2m9AT2CrALiN0sJicZEmgmgNqrvzX/4F8fCPLCu2HQP4KkvJ8UK FPYj/NuaROn/9u+oMmW22hKIpo/4gWuKgSOx9NhXsle3pneQNwigzL9jz5BVd3d/Ue/N lnEQ== X-Gm-Message-State: AOAM531CTGpbZBt8A0S+3Vc435Ps7yKQBEp75eIRCpoI3lsOUSnrnKdH 6PUpqRfwuSszU/WO3A/ayS8IkuO8RcunHfo8t5M= X-Google-Smtp-Source: ABdhPJyY7LLuloLJXgVNQFlfS9HdwIfDEPgFULArGUc1ChbKVaz1LF+I9iUuRXbeA9Rj/EyA4UmIXr9rTve272ID36o= X-Received: by 2002:a67:c094:: with SMTP id x20mr8612340vsi.53.1643163920689; Tue, 25 Jan 2022 18:25:20 -0800 (PST) MIME-Version: 1.0 References: <20220125153858.GA1609157@bhelgaas> In-Reply-To: <20220125153858.GA1609157@bhelgaas> From: Huacai Chen Date: Wed, 26 Jan 2022 10:25:14 +0800 Message-ID: Subject: Re: [PATCH v8 04/10] vgaarb: Move framebuffer detection to ADD_DEVICE path To: Bjorn Helgaas Cc: David Airlie , linux-pci , LKML , Maling list - DRI developers , =?UTF-8?Q?Bruno_Pr=C3=A9mont?= , Bjorn Helgaas , Xuefeng Li , Huacai Chen , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jan 25, 2022 at 11:39 PM Bjorn Helgaas wrote: > > [+cc Maarten, Maxime, Thomas; beginning of thread: > https://lore.kernel.org/r/20220106000658.243509-1-helgaas@kernel.org] > > On Tue, Jan 25, 2022 at 10:51:15AM +0800, Huacai Chen wrote: > > Hi, Bjorn, > > > > Why this series still missing in 5.17-rc1? :( > > 1) It was posted late in the cycle (Jan 6, when the merge window > opened Jan 9), so it was too late to expect a significant change like > this to be merged for v5.17. Right now is a good time to consider it > again so it would some time in -next. > > 2) As of now, this code is still in drivers/gpu, and I don't maintain > that area. It's up to the DRM folks, who are all cc'd here. > > I would like to move this from drivers/gpu to drivers/pci, but that > requires a little more work to resolve the initcall ordering problem > with respect to vga_arb_device_init() and misc_init() [1]. Hmm, to me, keep it in drivers/gpu is just OK. Huacai > > Bjorn > > [1] https://lore.kernel.org/linux-pci/CAAhV-H7FhAjM-Ha42Z1dLrE4PvC9frfyeU= 27KHWcyWKkMftEsA@mail.gmail.com/ > > > On Fri, Jan 7, 2022 at 12:21 AM Bjorn Helgaas wrot= e: > > > > > > On Thu, Jan 06, 2022 at 02:44:42PM +0800, Huacai Chen wrote: > > > > On Thu, Jan 6, 2022 at 8:07 AM Bjorn Helgaas w= rote: > > > > > Previously we selected a device that owns the boot framebuffer as= the > > > > > default device in vga_arb_select_default_device(). This was only= done in > > > > > the vga_arb_device_init() subsys_initcall, so devices enumerated = later, > > > > > e.g., by pcibios_init(), were not eligible. > > > > > > > > > > Fix this by moving the framebuffer device selection from > > > > > vga_arb_select_default_device() to vga_arbiter_add_pci_device(), = which is > > > > > called after every PCI device is enumerated, either by the > > > > > vga_arb_device_init() subsys_initcall or as an ADD_DEVICE notifie= r. > > > > > > > > > > Note that if vga_arb_select_default_device() found a device ownin= g the boot > > > > > framebuffer, it unconditionally set it to be the default VGA devi= ce, and no > > > > > subsequent device could replace it. > > > > > > > > > > Link: https://lore.kernel.org/r/20211015061512.2941859-7-chenhuac= ai@loongson.cn > > > > > Based-on-patch-by: Huacai Chen > > > > > Signed-off-by: Bjorn Helgaas > > > > > Cc: Bruno Pr=C3=A9mont > > > > > --- > > > > > drivers/gpu/vga/vgaarb.c | 37 +++++++++++++++++-----------------= --- > > > > > 1 file changed, 17 insertions(+), 20 deletions(-) > > > > > > > > > > diff --git a/drivers/gpu/vga/vgaarb.c b/drivers/gpu/vga/vgaarb.c > > > > > index b0ae0f177c6f..aefa4f406f7d 100644 > > > > > --- a/drivers/gpu/vga/vgaarb.c > > > > > +++ b/drivers/gpu/vga/vgaarb.c > > > > > @@ -72,6 +72,7 @@ struct vga_device { > > > > > unsigned int io_norm_cnt; /* normal IO count */ > > > > > unsigned int mem_norm_cnt; /* normal MEM count */ > > > > > bool bridge_has_one_vga; > > > > > + bool is_framebuffer; /* BAR covers firmware framebuffe= r */ > > > > > unsigned int (*set_decode)(struct pci_dev *pdev, bool dec= ode); > > > > > }; > > > > > > > > > > @@ -565,10 +566,9 @@ void vga_put(struct pci_dev *pdev, unsigned = int rsrc) > > > > > } > > > > > EXPORT_SYMBOL(vga_put); > > > > > > > > > > -static void __init vga_select_framebuffer_device(struct pci_dev = *pdev) > > > > > +static bool vga_is_framebuffer_device(struct pci_dev *pdev) > > > > > { > > > > > #if defined(CONFIG_X86) || defined(CONFIG_IA64) > > > > > - struct device *dev =3D &pdev->dev; > > > > > u64 base =3D screen_info.lfb_base; > > > > > u64 size =3D screen_info.lfb_size; > > > > > u64 limit; > > > > > @@ -583,15 +583,6 @@ static void __init vga_select_framebuffer_de= vice(struct pci_dev *pdev) > > > > > > > > > > limit =3D base + size; > > > > > > > > > > - /* > > > > > - * Override vga_arbiter_add_pci_device()'s I/O based dete= ction > > > > > - * as it may take the wrong device (e.g. on Apple system = under > > > > > - * EFI). > > > > > - * > > > > > - * Select the device owning the boot framebuffer if there= is > > > > > - * one. > > > > > - */ > > > > > - > > > > > /* Does firmware framebuffer belong to us? */ > > > > > for (i =3D 0; i < DEVICE_COUNT_RESOURCE; i++) { > > > > > flags =3D pci_resource_flags(pdev, i); > > > > > @@ -608,13 +599,10 @@ static void __init vga_select_framebuffer_d= evice(struct pci_dev *pdev) > > > > > if (base < start || limit >=3D end) > > > > > continue; > > > > > > > > > > - if (!vga_default_device()) > > > > > - vgaarb_info(dev, "setting as boot device\= n"); > > > > > - else if (pdev !=3D vga_default_device()) > > > > > - vgaarb_info(dev, "overriding boot device\= n"); > > > > > - vga_set_default_device(pdev); > > > > > + return true; > > > > > } > > > > > #endif > > > > > + return false; > > > > > } > > > > > > > > > > static bool vga_arb_integrated_gpu(struct device *dev) > > > > > @@ -635,6 +623,7 @@ static bool vga_arb_integrated_gpu(struct dev= ice *dev) > > > > > static bool vga_is_boot_device(struct vga_device *vgadev) > > > > > { > > > > > struct vga_device *boot_vga =3D vgadev_find(vga_default_d= evice()); > > > > > + struct pci_dev *pdev =3D vgadev->pdev; > > > > > > > > > > /* > > > > > * We select the default VGA device in this order: > > > > > @@ -645,6 +634,18 @@ static bool vga_is_boot_device(struct vga_de= vice *vgadev) > > > > > * Other device (see vga_arb_select_default_device()) > > > > > */ > > > > > > > > > > + /* > > > > > + * We always prefer a firmware framebuffer, so if we've a= lready > > > > > + * found one, there's no need to consider vgadev. > > > > > + */ > > > > > + if (boot_vga && boot_vga->is_framebuffer) > > > > > + return false; > > > > > + > > > > > + if (vga_is_framebuffer_device(pdev)) { > > > > > + vgadev->is_framebuffer =3D true; > > > > > + return true; > > > > > + } > > > > Maybe it is better to rename vga_is_framebuffer_device() to > > > > vga_is_firmware_device() and rename is_framebuffer to > > > > is_fw_framebuffer? > > > > > > That's a great point, thanks! > > > > > > The "framebuffer" term is way too generic. *All* VGA devices have a > > > framebuffer, so it adds no information. This is really about finding > > > the device that was used by firmware. > > > > > > I renamed: > > > > > > vga_is_framebuffer_device() -> vga_is_firmware_default() > > > vga_device.is_framebuffer -> vga_device.is_firmware_default > > > > > > I updated my local branch and pushed it to: > > > https://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci.git/log/?= h=3Dpci/vga > > > with head 0f4caffa1297 ("vgaarb: Replace full MIT license text with > > > SPDX identifier"). > > > > > > I don't maintain drivers/gpu/vga/vgaarb.c, so this branch is just for > > > reference. It'll ultimately be up to the DRM folks to handle this. > > > > > > I'll wait for any other comments or testing reports before reposting. > > > > > > > > /* > > > > > * A legacy VGA device has MEM and IO enabled and any bri= dges > > > > > * leading to it have PCI_BRIDGE_CTL_VGA enabled so the l= egacy > > > > > @@ -1531,10 +1532,6 @@ static void __init vga_arb_select_default_= device(void) > > > > > struct pci_dev *pdev, *found =3D NULL; > > > > > struct vga_device *vgadev; > > > > > > > > > > - list_for_each_entry(vgadev, &vga_list, list) { > > > > > - vga_select_framebuffer_device(vgadev->pdev); > > > > > - } > > > > > - > > > > > if (!vga_default_device()) { > > > > > list_for_each_entry_reverse(vgadev, &vga_list, li= st) { > > > > > struct device *dev =3D &vgadev->pdev->dev= ; > > > > > -- > > > > > 2.25.1 > > > > >