On Wed, Aug 21, 2024 at 04:48:23PM GMT, Thomas Zimmermann wrote:
Hi
Am 21.08.24 um 16:29 schrieb Jani Nikula:
On Wed, 21 Aug 2024, Gustavo Sousa <gustavo.sousa@xxxxxxxxx> wrote:
Quoting Thomas Zimmermann (2024-08-21 10:56:59-03:00)
Setting 'nomodeset' on the kernel command line disables all graphics
drivers with modesetting capabilities; leaving only firmware drivers,
such as simpledrm or efifb.
Most DRM drivers automatically support 'nomodeset' via DRM's module
helper macros. In xe, which uses regular module_init(), manually call
drm_firmware_drivers_only() to test for 'nomodeset'. Do not register
the driver if set.
Signed-off-by: Thomas Zimmermann <tzimmermann@xxxxxxx>
---
drivers/gpu/drm/xe/xe_module.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/drivers/gpu/drm/xe/xe_module.c b/drivers/gpu/drm/xe/xe_module.c
index 923460119cec..60fb7dd26903 100644
--- a/drivers/gpu/drm/xe/xe_module.c
+++ b/drivers/gpu/drm/xe/xe_module.c
@@ -8,6 +8,8 @@
#include <linux/init.h>
#include <linux/module.h>
+#include <drm/drm_module.h>
+
#include "xe_drv.h"
#include "xe_hw_fence.h"
#include "xe_pci.h"
@@ -92,6 +94,9 @@ static int __init xe_init(void)
{
int err, i;
+ if (drm_firmware_drivers_only())
+ return -ENODEV;
+
Hm... But what if xe is to be used only for compute or render? Shouldn't
we handle this somewhere else?
The question becomes, what does "nomodeset" really mean here?
That function's name 'firmware drivers only' says it better than the
option's name. We used 'nomodeset', because it was there already and
had the correct semantics.
agreed this should be on a module-level to maintain the behavior already
used. If we were not maintaining that behavior, then we should probably
not use "nomodeset" and choose something else :).
Also we already have the other 2 as module params: probe_display and
disable_display, with driver still registering as a drm driver, but
leaving the display part out.
Thomas, are you going to send a v2 to use the init table?
thanks
Lucas De Marchi
See what i915 does in i915_module.c.
i915 and the other drivers for PCI-based hardware don't load at all.
Drivers for external displays (e.g., SPI, USB) ignore nomodeset, as
these displays are not initialized by firmware.
Best regards
Thomas
Cc: Sima.
BR,
Jani.
Taking a quick look, xe_display_probe() might be a good candidate?
--
Gustavo Sousa
for (i = 0; i < ARRAY_SIZE(init_funcs); i++) {
err = init_funcs[i].init();
if (err) {
--
2.46.0
--
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstrasse 146, 90461 Nuernberg, Germany
GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman
HRB 36809 (AG Nuernberg)
