Re: [RFC v1 3/4] swiotlb: Allow dynamic allocation of bounce buffers

From: Juerg Haefliger
Date: Thu Apr 06 2023 - 07:58:47 EST


On Fri, 31 Mar 2023 11:00:43 +0200
Petr Tesařík <petr@xxxxxxxxxxx> wrote:

> Hi Juerg,
>
> On Fri, 31 Mar 2023 07:26:09 +0000
> Juerg Haefliger <juergh@xxxxxxxxx> wrote:
>
> > On Tue, 28 Mar 2023 09:54:35 +0200
> > Petr Tesarik <petrtesarik@xxxxxxxxxxxxxxx> wrote:
> >
> >[...]
> > > Anyway, I suspected that the buffers need not be imported into the vc4
> > > driver (also hinted by Eric Anholt in a 2018 blog post [1]), and it
> > > seems I was right. I encountered the issue with Ubuntu 22.10; I
> > > installed latest openSUSE Tumbleweed yesterday, and I was not able to
> > > reproduce the issue there, most likely because the Mesa drivers have
> > > been fixed meanwhile. This makes the specific case of the Raspberry Pi 4
> > > drivers moot. The issue may still affect other combinations of drivers,
> > > but I don't have any other real-world example ATM.
> >
> > I'm only seeing this problem with Wayland, no issue when switching Ubuntu to
> > X. It seems Tumbleweed is using X by default.
>
> I know; I was the team lead of SUSE low-level graphics engineers until
> end of last year... I have just double-checked, but this output of
> wayland-info in the GNOME session accessed over RDP is quite convincing:

It sure is but how did you get that?? For me it's:
$ wayland-info
failed to create display: No such file or directory

And from strace:
connect(3, {sa_family=AF_UNIX, sun_path="/run/user/1000/wayland-0"}, 27) = -1 ENOENT (No such file or directory)

Which is kind of expected when running X, no?
$ ps -ef | grep -iP 'xorg|wayland'
opensuse 1377 1375 0 09:13 tty2 00:00:16 /usr/bin/Xorg.bin vt2 -displayfd 3 -auth /run/user/1000/gdm/Xauthority -nolisten tcp -background none -noreset -keeptty -novtswitch -verbose 3

What am I missing?

...Juerg



> interface: 'wl_compositor', version: 5, name: 1
> interface: 'wl_shm', version: 1, name: 2
> formats (fourcc):
> 0x48344258 = 'XB4H'
> 0x48344241 = 'AB4H'
> 0x48345258 = 'XR4H'
> 0x48345241 = 'AR4H'
> 0x30334258 = 'XB30'
> 0x30334241 = 'AB30'
> 0x30335258 = 'XR30'
> 0x30335241 = 'AR30'
> 0x36314752 = 'RG16'
> 0x34324258 = 'XB24'
> 0x34324241 = 'AB24'
> 1 = 'XR24'
> 0 = 'AR24'
> interface: 'wl_output', version: 3, name: 3
> x: 0, y: 0, scale: 1,
> physical_width: 430 mm, physical_height: 270 mm,
> make: 'FUS', model: 'P20W-5 ECO',
> subpixel_orientation: unknown, output_transform: normal,
> mode:
> width: 1680 px, height: 1050 px, refresh: 59.954 Hz,
> flags: current preferred
> interface: 'zxdg_output_manager_v1', version: 3, name: 4
> xdg_output_v1
> output: 3
> name: 'HDMI-1'
> description: 'Fujitsu Siemens Computers GmbH 20"'
> logical_x: 0, logical_y: 0
> logical_width: 1680, logical_height: 1050
> interface: 'wl_data_device_manager', version: 3, name: 5
> interface: 'zwp_primary_selection_device_manager_v1', version: 1, name: 6
> interface: 'wl_subcompositor', version: 1, name: 7
> interface: 'xdg_wm_base', version: 4, name: 8
> interface: 'gtk_shell1', version: 5, name: 9
> interface: 'wp_viewporter', version: 1, name: 10
> interface: 'zwp_pointer_gestures_v1', version: 3, name: 11
> interface: 'zwp_tablet_manager_v2', version: 1, name: 12
> interface: 'wl_seat', version: 8, name: 13
> name: seat0
> capabilities: pointer keyboard
> keyboard repeat rate: 33
> keyboard repeat delay: 500
> interface: 'zwp_relative_pointer_manager_v1', version: 1, name: 14
> interface: 'zwp_pointer_constraints_v1', version: 1, name: 15
> interface: 'zxdg_exporter_v1', version: 1, name: 16
> interface: 'zxdg_importer_v1', version: 1, name: 17
> interface: 'zwp_linux_dmabuf_v1', version: 3, name: 18
> formats (fourcc) and modifiers (names):
> 0x48344258 = 'XB4H'; 0x00ffffffffffffff = INVALID
> 0x48344241 = 'AB4H'; 0x00ffffffffffffff = INVALID
> 0x36314752 = 'RG16'; 0x00ffffffffffffff = INVALID
> 0x30334258 = 'XB30'; 0x00ffffffffffffff = INVALID
> 0x30335258 = 'XR30'; 0x00ffffffffffffff = INVALID
> 0x30334241 = 'AB30'; 0x00ffffffffffffff = INVALID
> 0x30335241 = 'AR30'; 0x00ffffffffffffff = INVALID
> 0x34324258 = 'XB24'; 0x00ffffffffffffff = INVALID
> 0x34325258 = 'XR24'; 0x00ffffffffffffff = INVALID
> 0x34324241 = 'AB24'; 0x00ffffffffffffff = INVALID
> 0x34325241 = 'AR24'; 0x00ffffffffffffff = INVALID
> interface: 'wp_single_pixel_buffer_manager_v1', version: 1, name: 19
> interface: 'zwp_keyboard_shortcuts_inhibit_manager_v1', version: 1, name: 20
> interface: 'zwp_text_input_manager_v3', version: 1, name: 21
> interface: 'wp_presentation', version: 1, name: 22
> presentation clock id: 1 (CLOCK_MONOTONIC)
> interface: 'xdg_activation_v1', version: 1, name: 23
>
> Petr T

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