Re: [PATCH 00/60] drm: Make all drivers to honour the nomodeset parameter

[Thomas Zimmermann <tzimmermann@suse.de>]

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Hi Javier,

nothing wrong with your patches, but I'd like to propose slightly 
differnt solution.

For many USB drivers, you put the drm_firmware_drivers_only() call into 
the probe function. For registering, these drivers use 
module_usb_driver(), which expands to generic device-register functions.

I'd like to propose a similar macro for DRM drivers that includes the 
test for drm_firmware_drivers_only().

In drm_drv.h :

   #if defined(USB)
   static int drm_usb_register(struct usb_driver *usb)
   {
	if (drm_firmware_drivers_only())
		return -ENODEV;
	return usb_register_driver(usb);
   }
   #define drm_module_usb_driver(__usb)
	module_driver(drm_usb_register, usb_deregister)
   #endif

In each of the USB-based DRM drivers, replace module_usb_driver with 
drm_module_usb_driver.

And then there's PCI [3] and platform drivers, [4] which can be handled 
similarly. Many PCI drivers open-code the module init and device 
registering with the driver-specific enable parameter. Maybe adding a 
driver-specific register function would make sense.

Best regards
Thomas

[1] 
https://elixir.bootlin.com/linux/v5.15.8/source/include/linux/usb.h#L1306
[2] 
https://elixir.bootlin.com/linux/v5.15.8/source/include/linux/device/driver.h#L258
[3] 
https://elixir.bootlin.com/linux/v5.15.8/source/include/linux/pci.h#L1453
[4] 
https://elixir.bootlin.com/linux/v5.15.8/source/include/linux/platform_device.h#L251


Am 15.12.21 um 01:59 schrieb Javier Martinez Canillas:
> The nomodeset kernel command line parameter is used to prevent the KMS/DRM
> drivers to be registered/probed. But only a few drivers implement support
> for this parameter and most DRM drivers would just ignore it.
> 
> This (huge) patch series makes all DRM drivers to honour this parameter. It
> is posted as separate patches to make easier for drivers maintainers to ack
> or pick them independently at their own pace.
> 
> Patches are quite trivial and just add an if (drm_firmware_drivers_only())
> check and return -ENODEV if that's true. The condition is checked as early
> as possible, that is in the module_init handler for drivers that have one
> or in the probe function for drivers that are using the module_*_driver()
> macros and don't have their own module init function.
> 
> I included all the DRM drivers that think makes sense. I only left the vc4
> and v3d drivers, that Maxime is already handling in another patch series
> and the vgem, vkms and simpledrm drivers that should ignore the param IMO.
> 
> I've built tested with 'make allmodconfig && make M=drivers/gpu/drm/', but
> only booted in a few devices with and without nomodeset in the cmdline. So
> testing and reviewing for all the drivers would be highly appreciated.
> 
> Best regards,
> Javier
> 
> 
> Javier Martinez Canillas (60):
>    drm/komeda: Add support for the nomodeset kernel parameter
>    drm/arm/hdlcd: Add support for the nomodeset kernel parameter
>    drm/malidp: Add support for the nomodeset kernel parameter
>    drm/armada: Add support for the nomodeset kernel parameter
>    drm/aspeed: Add support for the nomodeset kernel parameter
>    drm/atmel-hlcdc: Add support for the nomodeset kernel parameter
>    drm/etnaviv: Add support for the nomodeset kernel parameter
>    drm/exynos: Add support for the nomodeset kernel parameter
>    drm/fsl-dcu: Add support for the nomodeset kernel parameter
>    drm/gma500: Add support for the nomodeset kernel parameter
>    drm/gud: Add support for the nomodeset kernel parameter
>    drm/hisilicon/hibmc: Add support for the nomodeset kernel parameter
>    drm/hisilicon/kirin: Add support for the nomodeset kernel parameter
>    drm/hyperv: Add support for the nomodeset kernel parameter
>    drm/i810: Add support for the nomodeset kernel parameter
>    drm/imx/dcss: Add support for the nomodeset kernel parameter
>    drm/imx: Add support for the nomodeset kernel parameter
>    drm/ingenic: Add support for the nomodeset kernel parameter
>    drm/kmb: Add support for the nomodeset kernel parameter
>    drm/lima: Add support for the nomodeset kernel parameter
>    drm/mcde: Add support for the nomodeset kernel parameter
>    drm/mediatek: Add support for the nomodeset kernel parameter
>    drm/meson: Add support for the nomodeset kernel parameter
>    drm/mga: Add support for the nomodeset kernel parameter
>    drm/msm: Add support for the nomodeset kernel parameter
>    drm: mxsfb: Add support for the nomodeset kernel parameter
>    drm/omap: Add support for the nomodeset kernel parameter
>    drm/panel: ilitek-ili9341: Add support for the nomodeset kernel
>      parameter
>    drm/panfrost: Add support for the nomodeset kernel parameter
>    drm/pl111: Add support for the nomodeset kernel parameter
>    drm/r128: Add support for the nomodeset kernel parameter
>    drm: rcar-du: Add support for the nomodeset kernel parameter
>    drm/rockchip: Add support for the nomodeset kernel parameter
>    drm/savage: Add support for the nomodeset kernel parameter
>    drm/shmobile: Add support for the nomodeset kernel parameter
>    drm/sis: Add support for the nomodeset kernel parameter
>    drm/sprd: Add support for the nomodeset kernel parameter
>    drm/sti: Add support for the nomodeset kernel parameter
>    drm/stm: Add support for the nomodeset kernel parameter
>    drm/sun4i: Add support for the nomodeset kernel parameter
>    drm/tdfx: Add support for the nomodeset kernel parameter
>    drm/tegra: Add support for the nomodeset kernel parameter
>    drm/tidss: Add support for the nomodeset kernel parameter
>    drm/tilcdc: Add support for the nomodeset kernel parameter
>    drm/arc: Add support for the nomodeset kernel parameter
>    drm/gm12u320: Add support for the nomodeset kernel parameter
>    drm/hx8357d: Add support for the nomodeset kernel parameter
>    drm/ili9163: Add support for the nomodeset kernel parameter
>    drm/ili9225: Add support for the nomodeset kernel parameter
>    drm/ili9341: Add support for the nomodeset kernel parameter
>    drm/ili9486: Add support for the nomodeset kernel parameter
>    drm/mi0283qt: Add support for the nomodeset kernel parameter
>    drm/repaper: Add support for the nomodeset kernel parameter
>    drm/st7586: Add support for the nomodeset kernel parameter
>    drm/st7735r: Add support for the nomodeset kernel parameter
>    drm/tve200: Add support for the nomodeset kernel parameter
>    drm/udl: Add support for the nomodeset kernel parameter
>    drm/via: Add support for the nomodeset kernel parameter
>    drm/xen: Add support for the nomodeset kernel parameter
>    drm/xlnx: Add support for the nomodeset kernel parameter
> 
>   drivers/gpu/drm/arm/display/komeda/komeda_drv.c | 4 ++++
>   drivers/gpu/drm/arm/hdlcd_drv.c                 | 3 +++
>   drivers/gpu/drm/arm/malidp_drv.c                | 3 +++
>   drivers/gpu/drm/armada/armada_drv.c             | 3 +++
>   drivers/gpu/drm/aspeed/aspeed_gfx_drv.c         | 3 +++
>   drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_dc.c    | 3 +++
>   drivers/gpu/drm/etnaviv/etnaviv_drv.c           | 3 +++
>   drivers/gpu/drm/exynos/exynos_drm_drv.c         | 3 +++
>   drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c       | 3 +++
>   drivers/gpu/drm/gma500/psb_drv.c                | 3 +++
>   drivers/gpu/drm/gud/gud_drv.c                   | 3 +++
>   drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c | 3 +++
>   drivers/gpu/drm/hisilicon/kirin/kirin_drm_drv.c | 3 +++
>   drivers/gpu/drm/hyperv/hyperv_drm_drv.c         | 3 +++
>   drivers/gpu/drm/i810/i810_drv.c                 | 3 +++
>   drivers/gpu/drm/imx/dcss/dcss-drv.c             | 3 +++
>   drivers/gpu/drm/imx/imx-drm-core.c              | 3 +++
>   drivers/gpu/drm/ingenic/ingenic-drm-drv.c       | 3 +++
>   drivers/gpu/drm/kmb/kmb_drv.c                   | 3 +++
>   drivers/gpu/drm/lima/lima_drv.c                 | 3 +++
>   drivers/gpu/drm/mcde/mcde_drv.c                 | 3 +++
>   drivers/gpu/drm/mediatek/mtk_drm_drv.c          | 3 +++
>   drivers/gpu/drm/meson/meson_drv.c               | 3 +++
>   drivers/gpu/drm/mga/mga_drv.c                   | 3 +++
>   drivers/gpu/drm/msm/msm_drv.c                   | 3 +++
>   drivers/gpu/drm/mxsfb/mxsfb_drv.c               | 3 +++
>   drivers/gpu/drm/omapdrm/omap_drv.c              | 3 +++
>   drivers/gpu/drm/panel/panel-ilitek-ili9341.c    | 3 +++
>   drivers/gpu/drm/panfrost/panfrost_drv.c         | 3 +++
>   drivers/gpu/drm/pl111/pl111_drv.c               | 3 +++
>   drivers/gpu/drm/r128/r128_drv.c                 | 3 +++
>   drivers/gpu/drm/rcar-du/rcar_du_drv.c           | 3 +++
>   drivers/gpu/drm/rockchip/rockchip_drm_drv.c     | 3 +++
>   drivers/gpu/drm/savage/savage_drv.c             | 3 +++
>   drivers/gpu/drm/shmobile/shmob_drm_drv.c        | 3 +++
>   drivers/gpu/drm/sis/sis_drv.c                   | 3 +++
>   drivers/gpu/drm/sprd/sprd_drm.c                 | 3 +++
>   drivers/gpu/drm/sti/sti_drv.c                   | 3 +++
>   drivers/gpu/drm/stm/drv.c                       | 3 +++
>   drivers/gpu/drm/sun4i/sun4i_drv.c               | 3 +++
>   drivers/gpu/drm/tdfx/tdfx_drv.c                 | 3 +++
>   drivers/gpu/drm/tegra/drm.c                     | 3 +++
>   drivers/gpu/drm/tidss/tidss_drv.c               | 3 +++
>   drivers/gpu/drm/tilcdc/tilcdc_drv.c             | 3 +++
>   drivers/gpu/drm/tiny/arcpgu.c                   | 3 +++
>   drivers/gpu/drm/tiny/gm12u320.c                 | 3 +++
>   drivers/gpu/drm/tiny/hx8357d.c                  | 3 +++
>   drivers/gpu/drm/tiny/ili9163.c                  | 3 +++
>   drivers/gpu/drm/tiny/ili9225.c                  | 3 +++
>   drivers/gpu/drm/tiny/ili9341.c                  | 3 +++
>   drivers/gpu/drm/tiny/ili9486.c                  | 3 +++
>   drivers/gpu/drm/tiny/mi0283qt.c                 | 3 +++
>   drivers/gpu/drm/tiny/repaper.c                  | 3 +++
>   drivers/gpu/drm/tiny/st7586.c                   | 3 +++
>   drivers/gpu/drm/tiny/st7735r.c                  | 3 +++
>   drivers/gpu/drm/tve200/tve200_drv.c             | 3 +++
>   drivers/gpu/drm/udl/udl_drv.c                   | 3 +++
>   drivers/gpu/drm/via/via_drv.c                   | 3 +++
>   drivers/gpu/drm/xen/xen_drm_front.c             | 3 +++
>   drivers/gpu/drm/xlnx/zynqmp_dpsub.c             | 3 +++
>   60 files changed, 181 insertions(+)
> 

-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Ivo Totev

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