diff --git a/src/boot/efi/console.c b/src/boot/efi/console.c index 241167b9f8..94551a89e1 100644 --- a/src/boot/efi/console.c +++ b/src/boot/efi/console.c @@ -20,6 +20,9 @@ #include "console.h" #include "util.h" +#define SYSTEM_FONT_WIDTH 8 +#define SYSTEM_FONT_HEIGHT 19 + #define EFI_SIMPLE_TEXT_INPUT_EX_PROTOCOL_GUID \ { 0xdd9e7534, 0x7762, 0x4698, { 0x8c, 0x14, 0xf5, 0x85, 0x17, 0xa6, 0x25, 0xaa } } @@ -148,9 +151,66 @@ static EFI_STATUS change_mode(UINTN mode) { return err; } +static UINT64 text_area_from_font_size(void) { + EFI_STATUS err; + UINT64 text_area; + UINTN rows, columns; + + err = uefi_call_wrapper(ST->ConOut->QueryMode, 4, ST->ConOut, ST->ConOut->Mode->Mode, &columns, &rows); + if (EFI_ERROR(err)) { + columns = 80; + rows = 25; + } + + text_area = SYSTEM_FONT_WIDTH * SYSTEM_FONT_HEIGHT * (UINT64)rows * (UINT64)columns; + + return text_area; +} + static EFI_STATUS mode_auto(UINTN *mode) { - /* Mode number 2 is first non standard mode, which is provided by - * the device manufacturer, so it should be a good mode. + const UINT32 HORIZONTAL_MAX_OK = 1920; + const UINT32 VERTICAL_MAX_OK = 1080; + const UINT64 VIEWPORT_RATIO = 10; + UINT64 screen_area, text_area; + EFI_GUID GraphicsOutputProtocolGuid = EFI_GRAPHICS_OUTPUT_PROTOCOL_GUID; + EFI_GRAPHICS_OUTPUT_PROTOCOL *GraphicsOutput; + EFI_GRAPHICS_OUTPUT_MODE_INFORMATION *Info; + EFI_STATUS err; + BOOLEAN keep = FALSE; + + err = LibLocateProtocol(&GraphicsOutputProtocolGuid, (VOID **)&GraphicsOutput); + if (!EFI_ERROR(err) && GraphicsOutput->Mode && GraphicsOutput->Mode->Info) { + Info = GraphicsOutput->Mode->Info; + + /* Start verifying if we are in a resolution larger than Full HD + * (1920x1080). If we're not, assume we're in a good mode and do not + * try to change it. */ + if (Info->HorizontalResolution <= HORIZONTAL_MAX_OK && Info->VerticalResolution <= VERTICAL_MAX_OK) + keep = TRUE; + /* For larger resolutions, calculate the ratio of the total screen + * area to the text viewport area. If it's less than 10 times bigger, + * then assume the text is readable and keep the text mode. */ + else { + screen_area = (UINT64)Info->HorizontalResolution * (UINT64)Info->VerticalResolution; + text_area = text_area_from_font_size(); + + if (text_area != 0 && screen_area/text_area < VIEWPORT_RATIO) + keep = TRUE; + } + } + + if (keep) { + /* Just clear the screen instead of changing the mode and return. */ + *mode = ST->ConOut->Mode->Mode; + uefi_call_wrapper(ST->ConOut->ClearScreen, 1, ST->ConOut); + return EFI_SUCCESS; + } + + /* If we reached here, then we have a high resolution screen and the text + * viewport is less than 10% the screen area, so the firmware developer + * screwed up. Try to switch to a better mode. Mode number 2 is first non + * standard mode, which is provided by the device manufacturer, so it should + * be a good mode. * Note: MaxMode is the number of modes, not the last mode. */ if (ST->ConOut->Mode->MaxMode > 2) *mode = 2;