Re: [PATCH] drm/mgag200: Don't read-back PCI option register before writing

[Jocelyn Falempe <jfalempe@xxxxxxxxxx>]

On 08/07/2022 09:21, Thomas Zimmermann wrote:
> Remove the read operation from mgag200_init_pci_options(). It was
> incorrectly added while refactoring the code. Reading the PCI option
> register clears the register's new value and subsequently leads to
> re-writing the old value.

Looks good to me.
Reviewed-by: Jocelyn Falempe <jfalempe@xxxxxxxxxx>

> Signed-off-by: Thomas Zimmermann <tzimmermann@xxxxxxx>
> Fixes: ce19021fd99a ("drm/mgag200: Move PCI-option setup into model-specific code")
> Cc: Thomas Zimmermann <tzimmermann@xxxxxxx>
> Cc: Jocelyn Falempe <jfalempe@xxxxxxxxxx>
> Cc: Dave Airlie <airlied@xxxxxxxxxx>
> Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx
> ---
>   drivers/gpu/drm/mgag200/mgag200_drv.c | 6 ------
>   1 file changed, 6 deletions(-)
>
> diff --git a/drivers/gpu/drm/mgag200/mgag200_drv.c b/drivers/gpu/drm/mgag200/mgag200_drv.c
> index 73e8e4e9e54b..251a1bb648cc 100644
> --- a/drivers/gpu/drm/mgag200/mgag200_drv.c
> +++ b/drivers/gpu/drm/mgag200/mgag200_drv.c
> @@ -28,12 +28,6 @@ int mgag200_init_pci_options(struct pci_dev *pdev, u32 option, u32 option2)
>   	struct device *dev = &pdev->dev;
>   	int err;
>   
> -	err = pci_read_config_dword(pdev, PCI_MGA_OPTION, &option);
> -	if (err != PCIBIOS_SUCCESSFUL) {
> -		dev_err(dev, "pci_read_config_dword(PCI_MGA_OPTION) failed: %d\n", err);
> -		return pcibios_err_to_errno(err);
> -	}
> -
>   	err = pci_write_config_dword(pdev, PCI_MGA_OPTION, option);
>   	if (err != PCIBIOS_SUCCESSFUL) {
>   		dev_err(dev, "pci_write_config_dword(PCI_MGA_OPTION) failed: %d\n", err);