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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D2B6FC433F5 for ; Tue, 9 Nov 2021 15:52:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B4AA561166 for ; Tue, 9 Nov 2021 15:52:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236482AbhKIPzX (ORCPT ); Tue, 9 Nov 2021 10:55:23 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47678 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235835AbhKIPzW (ORCPT ); Tue, 9 Nov 2021 10:55:22 -0500 Received: from smtp.domeneshop.no (smtp.domeneshop.no [IPv6:2a01:5b40:0:3005::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 775F6C061764 for ; Tue, 9 Nov 2021 07:52:36 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=tronnes.org ; s=ds202012; h=Content-Transfer-Encoding:Content-Type:In-Reply-To: MIME-Version:Date:Message-ID:From:References:Cc:To:Subject:Sender:Reply-To: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=K2jLWUxWVafTg6XNbuqQwSi/vlAJC5JC6VJT4lSLReA=; b=iPEDjmY4B+l5EgynojlyxUZtqa PYzpXHGLgun/+/iMFbKBQV1JftMh5fgtt+xl+IqF8Hn5oPfzXT0808tCeg+nrjsdnVcVSYJRrjS6i IGu8iiyCBaCgfpWei3QoRMC0cw6X7kREadu+SB+PumNhHBWjj0MkUM/YskCwqpRjvvaD0z22IcDSa vFldWUMNvxp3Rzu84TUUtnw+Wjnkh+6MWaKFJvHqOzSNgpVXztYTQFhwJB51P1Zo2ucmHsrD3AtUG sydZM8HYnflVH6XQsn5QbhWZMUa+CnHIeo7AMr6+7dRjrag0VVJXnLR4I4KB4o17e7h+yIaRaP86U /PuF/a/g==; Received: from 211.81-166-168.customer.lyse.net ([81.166.168.211]:60908 helo=[192.168.10.61]) by smtp.domeneshop.no with esmtpsa (TLS1.3:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.92) (envelope-from ) id 1mkTQH-0004KK-6r; Tue, 09 Nov 2021 16:52:33 +0100 Subject: Re: [PATCH v2 7/9] drm/simpledrm: Enable FB_DAMAGE_CLIPS property To: Thomas Zimmermann , daniel@ffwll.ch, airlied@linux.ie, mripard@kernel.org, maarten.lankhorst@linux.intel.com, drawat.floss@gmail.com, airlied@redhat.com, kraxel@redhat.com, david@lechnology.com, sam@ravnborg.org, javierm@redhat.com, kernel@amanoeldawod.com, dirty.ice.hu@gmail.com, michael+lkml@stapelberg.ch, aros@gmx.com, joshua@stroblindustries.com, arnd@arndb.de Cc: linux-hyperv@vger.kernel.org, dri-devel@lists.freedesktop.org, virtualization@lists.linux-foundation.org References: <20211101141532.26655-1-tzimmermann@suse.de> <20211101141532.26655-8-tzimmermann@suse.de> <974e10bb-ae58-d1c1-a89e-881b39da4930@tronnes.org> <1b1e8a38-2ad6-406e-0d07-bd28dcba08a3@tronnes.org> From: =?UTF-8?Q?Noralf_Tr=c3=b8nnes?= Message-ID: <6caaace4-27e5-2ac9-9c84-40d7b8ffcb1e@tronnes.org> Date: Tue, 9 Nov 2021 16:52:29 +0100 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.14.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-hyperv@vger.kernel.org Den 09.11.2021 15.56, skrev Thomas Zimmermann: > Hi, > > thanks for looking through all this code. > > Am 09.11.21 um 14:04 schrieb Noralf Trønnes: >> >> >> Den 09.11.2021 13.38, skrev Thomas Zimmermann: >>> >>> >>> Am 08.11.21 um 21:55 schrieb Noralf Trønnes: >>>> >>>> >>>> Den 01.11.2021 15.15, skrev Thomas Zimmermann: >>>>> Enable the FB_DAMAGE_CLIPS property to reduce display-update >>>>> overhead. Also fixes a warning in the kernel log. >>>>> >>>>>     simple-framebuffer simple-framebuffer.0: [drm] >>>>> drm_plane_enable_fb_damage_clips() not called >>>>> >>>>> Fix the computation of the blit rectangle. This wasn't an issue so >>>>> far, as simpledrm always blitted the full framebuffer. The code now >>>>> supports damage clipping and virtual screen sizes. >>>>> >>>>> Signed-off-by: Thomas Zimmermann >>>>> --- >>>>>    drivers/gpu/drm/tiny/simpledrm.c | 30 >>>>> ++++++++++++++++++++++-------- >>>>>    1 file changed, 22 insertions(+), 8 deletions(-) >>>>> >>>>> diff --git a/drivers/gpu/drm/tiny/simpledrm.c >>>>> b/drivers/gpu/drm/tiny/simpledrm.c >>>>> index 571f716ff427..e872121e9fb0 100644 >>>>> --- a/drivers/gpu/drm/tiny/simpledrm.c >>>>> +++ b/drivers/gpu/drm/tiny/simpledrm.c >>>>> @@ -642,7 +642,7 @@ simpledrm_simple_display_pipe_enable(struct >>>>> drm_simple_display_pipe *pipe, >>>>>        void *vmap = shadow_plane_state->data[0].vaddr; /* TODO: Use >>>>> mapping abstraction */ >>>>>        struct drm_device *dev = &sdev->dev; >>>>>        void __iomem *dst = sdev->screen_base; >>>>> -    struct drm_rect clip; >>>>> +    struct drm_rect src_clip, dst_clip; >>>>>        int idx; >>>>>          if (!fb) >>>>> @@ -651,10 +651,14 @@ simpledrm_simple_display_pipe_enable(struct >>>>> drm_simple_display_pipe *pipe, >>>>>        if (!drm_dev_enter(dev, &idx)) >>>>>            return; >>>>>    -    drm_rect_init(&clip, 0, 0, fb->width, fb->height); >>>>> +    drm_rect_fp_to_int(&src_clip, &plane_state->src); >>>>>    -    dst += drm_fb_clip_offset(sdev->pitch, sdev->format, &clip); >>>>> -    drm_fb_blit_toio(dst, sdev->pitch, sdev->format->format, vmap, >>>>> fb, &clip); >>>>> +    dst_clip = plane_state->dst; >>>> >>>> I assume that src_clip and dst_clip are of the same size, since scaling >>>> is not supported. What prevents dst_clip from being bigger than the >>>> buffer that's being blitted into? Where is that bounds checking done? >>> >>> The value of dst_clip comes from plane_state->dst, which gets >>> initialized in drm_atomic_helper_check_plane_state(). [1] The fields are >>> taken from the crtc_{x,y,w,h} values by drm_plane_get_dest(). [2] For >>> primary planes, the crtc_{x,y,w,h} values are initialized in >>> __drm_atomic_helper_set_config() to the size of the display. [3] That >>> size comes directly from the current video mode. [4] From all I can see >>> this cannot overflow. >>> >> >> Ok, that takes care of the upper bound. >> >> There's this in drm_atomic_helper_check_plane_state(): >> >>     plane_state->visible = drm_rect_clip_scaled(src, dst, &clip); >> >>     if (!plane_state->visible) >>         /* >>          * Plane isn't visible; some drivers can handle this >>          * so we just return success here.  Drivers that can't >>          * (including those that use the primary plane helper's >>          * update function) will return an error from their >>          * update_plane handler. >>          */ >>         return 0; >> >> drm_atomic_helper_damage_merged() checks ->visible and returns false if >> it is not set so update() is good on the lower bound. >> >> Maybe it's necessary to check ->visible here in enable() before doing >> the blit? > > Is it even possible to create an invisible primary plane here? We cannot > scale [1] and if the primary plane is smaller than the framebuffer, we > hit the case at [2]. The only way I can see this is that the visibility > test at [3] succeeds. That would require a framebuffer of size 0. That's > impossible from the code in frambuffer_check(). [4] Unless there's some > corner case, we're good here. Ok, thanks. Noralf. > > However, I think that drm_atomic_check_plane_state() could later be > improved to handle the 'visible' field in a more sophisticated way. > > Best regards > Thomas > > [1] > https://elixir.bootlin.com/linux/latest/source/drivers/gpu/drm/drm_simple_kms_helper.c#L227 > > [2] > https://elixir.bootlin.com/linux/latest/source/drivers/gpu/drm/drm_atomic_helper.c#L854 > > [3] > https://elixir.bootlin.com/linux/latest/source/drivers/gpu/drm/drm_atomic_helper.c#L844 > > [4] > https://elixir.bootlin.com/linux/latest/source/drivers/gpu/drm/drm_framebuffer.c#L185 > > >> >> Noralf. >> >>> Best regards >>> Thomas >>> >>> [1] >>> https://elixir.bootlin.com/linux/latest/source/drivers/gpu/drm/drm_atomic_helper.c#L807 >>> >>> >>> [2] >>> https://elixir.bootlin.com/linux/latest/source/include/drm/drm_plane.h#L257 >>> >>> [3] >>> https://elixir.bootlin.com/linux/latest/source/drivers/gpu/drm/drm_atomic.c#L1590 >>> >>> >>> [4] >>> https://elixir.bootlin.com/linux/latest/source/drivers/gpu/drm/drm_modes.c#L788 >>> >>> >>> >>>> >>>> Noralf. >>>> >>>>> +    if (!drm_rect_intersect(&dst_clip, &src_clip)) >>>>> +        return; >>>>> + >>>>> +    dst += drm_fb_clip_offset(sdev->pitch, sdev->format, &dst_clip); >>>>> +    drm_fb_blit_toio(dst, sdev->pitch, sdev->format->format, vmap, >>>>> fb, &src_clip); >>>>>          drm_dev_exit(idx); >>>>>    } >>>>> @@ -686,20 +690,28 @@ simpledrm_simple_display_pipe_update(struct >>>>> drm_simple_display_pipe *pipe, >>>>>        struct drm_framebuffer *fb = plane_state->fb; >>>>>        struct drm_device *dev = &sdev->dev; >>>>>        void __iomem *dst = sdev->screen_base; >>>>> -    struct drm_rect clip; >>>>> +    struct drm_rect damage_clip, src_clip, dst_clip; >>>>>        int idx; >>>>>          if (!fb) >>>>>            return; >>>>>    -    if (!drm_atomic_helper_damage_merged(old_plane_state, >>>>> plane_state, &clip)) >>>>> +    if (!drm_atomic_helper_damage_merged(old_plane_state, >>>>> plane_state, &damage_clip)) >>>>> +        return; >>>>> + >>>>> +    drm_rect_fp_to_int(&src_clip, &plane_state->src); >>>>> +    if (!drm_rect_intersect(&src_clip, &damage_clip)) >>>>> +        return; >>>>> + >>>>> +    dst_clip = plane_state->dst; >>>>> +    if (!drm_rect_intersect(&dst_clip, &src_clip)) >>>>>            return; >>>>>          if (!drm_dev_enter(dev, &idx)) >>>>>            return; >>>>>    -    dst += drm_fb_clip_offset(sdev->pitch, sdev->format, &clip); >>>>> -    drm_fb_blit_toio(dst, sdev->pitch, sdev->format->format, vmap, >>>>> fb, &clip); >>>>> +    dst += drm_fb_clip_offset(sdev->pitch, sdev->format, &dst_clip); >>>>> +    drm_fb_blit_toio(dst, sdev->pitch, sdev->format->format, vmap, >>>>> fb, &src_clip); >>>>>          drm_dev_exit(idx); >>>>>    } >>>>> @@ -794,6 +806,8 @@ static int simpledrm_device_init_modeset(struct >>>>> simpledrm_device *sdev) >>>>>        if (ret) >>>>>            return ret; >>>>>    +    drm_plane_enable_fb_damage_clips(&pipe->plane); >>>>> + >>>>>        drm_mode_config_reset(dev); >>>>>          return 0; >>>>> >>> >