Re: [PATCH v2 5/9] vgacon: remove screen_info dependency

Khalid Aziz
2023-07-20T19:09:14Z

On 7/19/23 6:39 AM, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@arndb.de>
>
> The vga console driver is fairly self-contained, and only used by
> architectures that explicitly initialize the screen_info settings.
>
> Chance every instance that picks the vga console by setting conswitchp
> to call a function instead, and pass a reference to the screen_info
> there.
>
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>

PCDP and ia64 changes look good to me.

Acked-by: Khalid Azzi <khalid@gonehiking.org>

> ---
> arch/alpha/kernel/setup.c | 2 +-
> arch/arm/kernel/setup.c | 2 +-
> arch/ia64/kernel/setup.c | 2 +-
> arch/mips/kernel/setup.c | 2 +-
> arch/x86/kernel/setup.c | 2 +-
> drivers/firmware/pcdp.c | 2 +-
> drivers/video/console/vgacon.c | 68 ++++++++++++++++++++--------------
> include/linux/console.h | 7 ++++
> 8 files changed, 53 insertions(+), 34 deletions(-)
>
> diff --git a/arch/alpha/kernel/setup.c b/arch/alpha/kernel/setup.c
> index b4d2297765c02..d73b685fe9852 100644
> --- a/arch/alpha/kernel/setup.c
> +++ b/arch/alpha/kernel/setup.c
> @@ -655,7 +655,7 @@ setup_arch(char **cmdline_p)
>
> #ifdef CONFIG_VT
> #if defined(CONFIG_VGA_CONSOLE)
> - conswitchp = &vga_con;
> + vgacon_register_screen(&screen_info);
> #endif
> #endif
>
> diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c
> index 40326a35a179b..5d8a7fb3eba45 100644
> --- a/arch/arm/kernel/setup.c
> +++ b/arch/arm/kernel/setup.c
> @@ -1192,7 +1192,7 @@ void __init setup_arch(char **cmdline_p)
>
> #ifdef CONFIG_VT
> #if defined(CONFIG_VGA_CONSOLE)
> - conswitchp = &vga_con;
> + vgacon_register_screen(&screen_info);
> #endif
> #endif
>
> diff --git a/arch/ia64/kernel/setup.c b/arch/ia64/kernel/setup.c
> index d2c66efdde560..2c9283fcd3759 100644
> --- a/arch/ia64/kernel/setup.c
> +++ b/arch/ia64/kernel/setup.c
> @@ -619,7 +619,7 @@ setup_arch (char **cmdline_p)
> * memory so we can avoid this problem.
> */
> if (efi_mem_type(0xA0000) != EFI_CONVENTIONAL_MEMORY)
> - conswitchp = &vga_con;
> + vgacon_register_screen(&screen_info);
> # endif
> }
> #endif
> diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c
> index 1aba7dc95132c..6c3fae62a9f6b 100644
> --- a/arch/mips/kernel/setup.c
> +++ b/arch/mips/kernel/setup.c
> @@ -794,7 +794,7 @@ void __init setup_arch(char **cmdline_p)
>
> #if defined(CONFIG_VT)
> #if defined(CONFIG_VGA_CONSOLE)
> - conswitchp = &vga_con;
> + vgacon_register_screen(&screen_info);
> #endif
> #endif
>
> diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
> index fd975a4a52006..b1ea77d504615 100644
> --- a/arch/x86/kernel/setup.c
> +++ b/arch/x86/kernel/setup.c
> @@ -1293,7 +1293,7 @@ void __init setup_arch(char **cmdline_p)
> #ifdef CONFIG_VT
> #if defined(CONFIG_VGA_CONSOLE)
> if (!efi_enabled(EFI_BOOT) || (efi_mem_type(0xa0000) != EFI_CONVENTIONAL_MEMORY))
> - conswitchp = &vga_con;
> + vgacon_register_screen(&screen_info);
> #endif
> #endif
> x86_init.oem.banner();
> diff --git a/drivers/firmware/pcdp.c b/drivers/firmware/pcdp.c
> index 715a45442d1cf..667a595373b2d 100644
> --- a/drivers/firmware/pcdp.c
> +++ b/drivers/firmware/pcdp.c
> @@ -72,7 +72,7 @@ setup_vga_console(struct pcdp_device *dev)
> return -ENODEV;
> }
>
> - conswitchp = &vga_con;
> + vgacon_register_screen(&screen_info);
> printk(KERN_INFO "PCDP: VGA console\n");
> return 0;
> #else
> diff --git a/drivers/video/console/vgacon.c b/drivers/video/console/vgacon.c
> index e25ba523892e5..3d7fedf27ffc1 100644
> --- a/drivers/video/console/vgacon.c
> +++ b/drivers/video/console/vgacon.c
> @@ -97,6 +97,8 @@ static int vga_video_font_height;
> static int vga_scan_lines __read_mostly;
> static unsigned int vga_rolled_over; /* last vc_origin offset before wrap */
>
> +static struct screen_info *vga_si;
> +
> static bool vga_hardscroll_enabled;
> static bool vga_hardscroll_user_enable = true;
>
> @@ -161,8 +163,9 @@ static const char *vgacon_startup(void)
> u16 saved1, saved2;
> volatile u16 *p;
>
> - if (screen_info.orig_video_isVGA == VIDEO_TYPE_VLFB ||
> - screen_info.orig_video_isVGA == VIDEO_TYPE_EFI) {
> + if (!vga_si ||
> + vga_si->orig_video_isVGA == VIDEO_TYPE_VLFB ||
> + vga_si->orig_video_isVGA == VIDEO_TYPE_EFI) {
> no_vga:
> #ifdef CONFIG_DUMMY_CONSOLE
> conswitchp = &dummy_con;
> @@ -172,29 +175,29 @@ static const char *vgacon_startup(void)
> #endif
> }
>
> - /* boot_params.screen_info reasonably initialized? */
> - if ((screen_info.orig_video_lines == 0) ||
> - (screen_info.orig_video_cols == 0))
> + /* vga_si reasonably initialized? */
> + if ((vga_si->orig_video_lines == 0) ||
> + (vga_si->orig_video_cols == 0))
> goto no_vga;
>
> /* VGA16 modes are not handled by VGACON */
> - if ((screen_info.orig_video_mode == 0x0D) || /* 320x200/4 */
> - (screen_info.orig_video_mode == 0x0E) || /* 640x200/4 */
> - (screen_info.orig_video_mode == 0x10) || /* 640x350/4 */
> - (screen_info.orig_video_mode == 0x12) || /* 640x480/4 */
> - (screen_info.orig_video_mode == 0x6A)) /* 800x600/4 (VESA) */
> + if ((vga_si->orig_video_mode == 0x0D) || /* 320x200/4 */
> + (vga_si->orig_video_mode == 0x0E) || /* 640x200/4 */
> + (vga_si->orig_video_mode == 0x10) || /* 640x350/4 */
> + (vga_si->orig_video_mode == 0x12) || /* 640x480/4 */
> + (vga_si->orig_video_mode == 0x6A)) /* 800x600/4 (VESA) */
> goto no_vga;
>
> - vga_video_num_lines = screen_info.orig_video_lines;
> - vga_video_num_columns = screen_info.orig_video_cols;
> + vga_video_num_lines = vga_si->orig_video_lines;
> + vga_video_num_columns = vga_si->orig_video_cols;
> vgastate.vgabase = NULL;
>
> - if (screen_info.orig_video_mode == 7) {
> + if (vga_si->orig_video_mode == 7) {
> /* Monochrome display */
> vga_vram_base = 0xb0000;
> vga_video_port_reg = VGA_CRT_IM;
> vga_video_port_val = VGA_CRT_DM;
> - if ((screen_info.orig_video_ega_bx & 0xff) != 0x10) {
> + if ((vga_si->orig_video_ega_bx & 0xff) != 0x10) {
> static struct resource ega_console_resource =
> { .name = "ega",
> .flags = IORESOURCE_IO,
> @@ -231,12 +234,12 @@ static const char *vgacon_startup(void)
> vga_vram_base = 0xb8000;
> vga_video_port_reg = VGA_CRT_IC;
> vga_video_port_val = VGA_CRT_DC;
> - if ((screen_info.orig_video_ega_bx & 0xff) != 0x10) {
> + if ((vga_si->orig_video_ega_bx & 0xff) != 0x10) {
> int i;
>
> vga_vram_size = 0x8000;
>
> - if (!screen_info.orig_video_isVGA) {
> + if (!vga_si->orig_video_isVGA) {
> static struct resource ega_console_resource =
> { .name = "ega",
> .flags = IORESOURCE_IO,
> @@ -327,14 +330,14 @@ static const char *vgacon_startup(void)
> || vga_video_type == VIDEO_TYPE_VGAC
> || vga_video_type == VIDEO_TYPE_EGAM) {
> vga_hardscroll_enabled = vga_hardscroll_user_enable;
> - vga_default_font_height = screen_info.orig_video_points;
> - vga_video_font_height = screen_info.orig_video_points;
> + vga_default_font_height = vga_si->orig_video_points;
> + vga_video_font_height = vga_si->orig_video_points;
> /* This may be suboptimal but is a safe bet - go with it */
> vga_scan_lines =
> vga_video_font_height * vga_video_num_lines;
> }
>
> - vgacon_xres = screen_info.orig_video_cols * VGA_FONTWIDTH;
> + vgacon_xres = vga_si->orig_video_cols * VGA_FONTWIDTH;
> vgacon_yres = vga_scan_lines;
>
> return display_desc;
> @@ -379,7 +382,7 @@ static void vgacon_init(struct vc_data *c, int init)
> /* Only set the default if the user didn't deliberately override it */
> if (global_cursor_default == -1)
> global_cursor_default =
> - !(screen_info.flags & VIDEO_FLAGS_NOCURSOR);
> + !(vga_si->flags & VIDEO_FLAGS_NOCURSOR);
> }
>
> static void vgacon_deinit(struct vc_data *c)
> @@ -607,7 +610,7 @@ static int vgacon_switch(struct vc_data *c)
> {
> int x = c->vc_cols * VGA_FONTWIDTH;
> int y = c->vc_rows * c->vc_cell_height;
> - int rows = screen_info.orig_video_lines * vga_default_font_height/
> + int rows = vga_si->orig_video_lines * vga_default_font_height/
> c->vc_cell_height;
> /*
> * We need to save screen size here as it's the only way
> @@ -627,7 +630,7 @@ static int vgacon_switch(struct vc_data *c)
>
> if ((vgacon_xres != x || vgacon_yres != y) &&
> (!(vga_video_num_columns % 2) &&
> - vga_video_num_columns <= screen_info.orig_video_cols &&
> + vga_video_num_columns <= vga_si->orig_video_cols &&
> vga_video_num_lines <= rows))
> vgacon_doresize(c, c->vc_cols, c->vc_rows);
> }
> @@ -1074,13 +1077,13 @@ static int vgacon_resize(struct vc_data *c, unsigned int width,
> * Ho ho! Someone (svgatextmode, eh?) may have reprogrammed
> * the video mode! Set the new defaults then and go away.
> */
> - screen_info.orig_video_cols = width;
> - screen_info.orig_video_lines = height;
> + vga_si->orig_video_cols = width;
> + vga_si->orig_video_lines = height;
> vga_default_font_height = c->vc_cell_height;
> return 0;
> }
> - if (width % 2 || width > screen_info.orig_video_cols ||
> - height > (screen_info.orig_video_lines * vga_default_font_height)/
> + if (width % 2 || width > vga_si->orig_video_cols ||
> + height > (vga_si->orig_video_lines * vga_default_font_height)/
> c->vc_cell_height)
> return -EINVAL;
>
> @@ -1110,8 +1113,8 @@ static void vgacon_save_screen(struct vc_data *c)
> * console initialization routines.
> */
> vga_bootup_console = 1;
> - c->state.x = screen_info.orig_x;
> - c->state.y = screen_info.orig_y;
> + c->state.x = vga_si->orig_x;
> + c->state.y = vga_si->orig_y;
> }
>
> /* We can't copy in more than the size of the video buffer,
> @@ -1204,4 +1207,13 @@ const struct consw vga_con = {
> };
> EXPORT_SYMBOL(vga_con);
>
> +void vgacon_register_screen(struct screen_info *si)
> +{
> + if (!si || vga_si)
> + return;
> +
> + conswitchp = &vga_con;
> + vga_si = si;
> +}
> +
> MODULE_LICENSE("GPL");
> diff --git a/include/linux/console.h b/include/linux/console.h
> index d3195664baa5a..5f900210e689e 100644
> --- a/include/linux/console.h
> +++ b/include/linux/console.h
> @@ -101,6 +101,13 @@ extern const struct consw dummy_con; /* dummy console buffer */
> extern const struct consw vga_con; /* VGA text console */
> extern const struct consw newport_con; /* SGI Newport console */
>
> +struct screen_info;
> +#ifdef CONFIG_VGA_CONSOLE
> +void vgacon_register_screen(struct screen_info *si);
> +#else
> +static inline void vgacon_register_screen(struct screen_info *si) { }
> +#endif
> +
> int con_is_bound(const struct consw *csw);
> int do_unregister_con_driver(const struct consw *csw);
> int do_take_over_console(const struct consw *sw, int first, int last, int deflt);