From: Arvind Sankar <nivedita@xxxxxxxxxxxx> Add the ability to automatically pick the highest resolution video mode (defined as the product of vertical and horizontal resolution) by using a command-line argument of the form video=efifb:auto If there are multiple modes with the highest resolution, pick one with the highest color depth. Signed-off-by: Arvind Sankar <nivedita@xxxxxxxxxxxx> Link: https://lore.kernel.org/r/20200328160601.378299-2-nivedita@xxxxxxxxxxxx Signed-off-by: Ard Biesheuvel <ardb@xxxxxxxxxx> --- Documentation/fb/efifb.rst | 6 +++ drivers/firmware/efi/libstub/gop.c | 84 +++++++++++++++++++++++++++++- 2 files changed, 89 insertions(+), 1 deletion(-) diff --git a/Documentation/fb/efifb.rst b/Documentation/fb/efifb.rst index eca38466487a..519550517fd4 100644 --- a/Documentation/fb/efifb.rst +++ b/Documentation/fb/efifb.rst @@ -57,4 +57,10 @@ mode=n "rgb" or "bgr" to match specifically those pixel formats, or a number for a mode with matching bits per pixel. +auto + The EFI stub will choose the mode with the highest resolution (product + of horizontal and vertical resolution). If there are multiple modes + with the highest resolution, it will choose one with the highest color + depth. + Edgar Hucek <gimli@xxxxxxxxxxxxxx> diff --git a/drivers/firmware/efi/libstub/gop.c b/drivers/firmware/efi/libstub/gop.c index 848cb605a9c4..fa05a0b0adfd 100644 --- a/drivers/firmware/efi/libstub/gop.c +++ b/drivers/firmware/efi/libstub/gop.c @@ -18,7 +18,8 @@ enum efi_cmdline_option { EFI_CMDLINE_NONE, EFI_CMDLINE_MODE_NUM, - EFI_CMDLINE_RES + EFI_CMDLINE_RES, + EFI_CMDLINE_AUTO }; static struct { @@ -86,6 +87,19 @@ static bool parse_res(char *option, char **next) return true; } +static bool parse_auto(char *option, char **next) +{ + if (!strstarts(option, "auto")) + return false; + option += strlen("auto"); + if (*option && *option++ != ',') + return false; + cmdline.option = EFI_CMDLINE_AUTO; + + *next = option; + return true; +} + void efi_parse_option_graphics(char *option) { while (*option) { @@ -93,6 +107,8 @@ void efi_parse_option_graphics(char *option) continue; if (parse_res(option, &option)) continue; + if (parse_auto(option, &option)) + continue; while (*option && *option++ != ',') ; @@ -211,6 +227,69 @@ static u32 choose_mode_res(efi_graphics_output_protocol_t *gop) return cur_mode; } +static u32 choose_mode_auto(efi_graphics_output_protocol_t *gop) +{ + efi_status_t status; + + efi_graphics_output_protocol_mode_t *mode; + efi_graphics_output_mode_info_t *info; + unsigned long info_size; + + u32 max_mode, cur_mode, best_mode, area; + u8 depth; + int pf; + efi_pixel_bitmask_t pi; + u32 m, w, h, a; + u8 d; + + mode = efi_table_attr(gop, mode); + + cur_mode = efi_table_attr(mode, mode); + max_mode = efi_table_attr(mode, max_mode); + + info = efi_table_attr(mode, info); + + pf = info->pixel_format; + pi = info->pixel_information; + w = info->horizontal_resolution; + h = info->vertical_resolution; + + best_mode = cur_mode; + area = w * h; + depth = pixel_bpp(pf, pi); + + for (m = 0; m < max_mode; m++) { + if (m == cur_mode) + continue; + + status = efi_call_proto(gop, query_mode, m, + &info_size, &info); + if (status != EFI_SUCCESS) + continue; + + pf = info->pixel_format; + pi = info->pixel_information; + w = info->horizontal_resolution; + h = info->vertical_resolution; + + efi_bs_call(free_pool, info); + + if (pf == PIXEL_BLT_ONLY || pf >= PIXEL_FORMAT_MAX) + continue; + a = w * h; + if (a < area) + continue; + d = pixel_bpp(pf, pi); + if (a > area || d > depth) { + best_mode = m; + area = a; + depth = d; + } + } + + return best_mode; +} + static void set_mode(efi_graphics_output_protocol_t *gop) { efi_graphics_output_protocol_mode_t *mode; @@ -223,6 +302,9 @@ static void set_mode(efi_graphics_output_protocol_t *gop) case EFI_CMDLINE_RES: new_mode = choose_mode_res(gop); break; + case EFI_CMDLINE_AUTO: + new_mode = choose_mode_auto(gop); + break; default: return; } -- 2.17.1
