UMS: Fix lockups in palette save/restore on pre-AVIVO chips.

The reintroduction of palette save/restore in 5efdf514 causes some
pre-AVIVO chips to lock up. An investigation revealed that accessing
palette registers when the associated PLL is not running is causing
this. With UMS the PLL setup that is saved has been done by the BIOS
typically.
A similar issue was observed when VGA palette save/restore had
been reinitroduced with 80eee856:
 http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=480312
and has been worked around for Linux without further investigation
by 87e66ce7.
To fix the issue we now
a. introduce 'on-demand' palette saving (ie the palette is
   saved before it is first altered). This guarantees that
   the palette register are only associated when the associated
   CRTC is active and thus the PLLs are powered up and running.
b. move palette restore before PLL restore.
c. eliminate generic VGA palette save/restore which seems to be
   unneeded when the palette is restored natively.
   It is believed that this caused the behavior described in
   https://bugs.freedesktop.org/show_bug.cgi?id=18407#c27

Signed-off-by: Egbert Eich <eich@freedesktop.org>
Reviewed-by: Alex Deucher <alexdeucher@gmail.com>

4 files changed, 40 insertions, 28 deletions

diff --git a/src/radeon.h b/src/radeon.h
index 91c7b624..3f7ad4e6 100644
--- a/src/radeon.h
+++ b/src/radeon.h
@@ -1072,6 +1072,7 @@ extern void RADEONRestoreLVDSRegisters(ScrnInfoPtr pScrn, RADEONSavePtr restore)
 extern void RADEONRestoreRMXRegisters(ScrnInfoPtr pScrn, RADEONSavePtr restore);
 extern void RADEONSaveDACRegisters(ScrnInfoPtr pScrn, RADEONSavePtr save);
 extern void RADEONSaveFPRegisters(ScrnInfoPtr pScrn, RADEONSavePtr save);
+extern void radeon_save_palette_on_demand(ScrnInfoPtr pScrn, int palID);
 
 extern void RADEONGetTVDacAdjInfo(ScrnInfoPtr pScrn, radeon_tvdac_ptr tvdac);
 extern void RADEONGetTMDSInfoFromTable(ScrnInfoPtr pScrn, radeon_tmds_ptr tmds);
diff --git a/src/radeon_crtc.c b/src/radeon_crtc.c
index 3c037001..9821ab60 100644
--- a/src/radeon_crtc.c
+++ b/src/radeon_crtc.c
@@ -510,6 +510,8 @@ radeon_crtc_load_lut(xf86CrtcPtr crtc)
     if (!crtc->enabled)
 	return;
 
+    radeon_save_palette_on_demand(pScrn, radeon_crtc->crtc_id);
+
     if (IS_DCE4_VARIANT) {
 	OUTREG(EVERGREEN_DC_LUT_CONTROL + radeon_crtc->crtc_offset, 0);
 
diff --git a/src/radeon_driver.c b/src/radeon_driver.c
index 81f5645a..04a242a7 100644
--- a/src/radeon_driver.c
+++ b/src/radeon_driver.c
@@ -4477,22 +4477,17 @@ static void RADEONSaveMemMapRegisters(ScrnInfoPtr pScrn, RADEONSavePtr save)
 }
 
 /* Read palette data */
-static void RADEONSavePalette(ScrnInfoPtr pScrn, RADEONSavePtr save)
+static void RADEONSavePalette(ScrnInfoPtr pScrn, int palID, RADEONSavePtr save)
 {
     RADEONInfoPtr  info       = RADEONPTR(pScrn);
     unsigned char *RADEONMMIO = info->MMIO;
     int            i;
 
-    PAL_SELECT(1);
+    PAL_SELECT(palID);
     INPAL_START(0);
-    for (i = 0; i < 256; i++) {
-	save->palette2[i] = INREG(RADEON_PALETTE_30_DATA);
-    }
 
-    PAL_SELECT(0);
-    INPAL_START(0);
     for (i = 0; i < 256; i++) {
-	save->palette[i] = INREG(RADEON_PALETTE_30_DATA);
+	save->palette[palID][i] = INREG(RADEON_PALETTE_30_DATA);
     }
 }
 
@@ -4502,16 +4497,21 @@ static void RADEONRestorePalette(ScrnInfoPtr pScrn, RADEONSavePtr restore)
     unsigned char *RADEONMMIO = info->MMIO;
     int            i;
 
-    PAL_SELECT(1);
-    OUTPAL_START(0);
-    for (i = 0; i < 256; i++) {
-	OUTREG(RADEON_PALETTE_30_DATA, restore->palette2[i]);
+    if (restore->palette_saved[1]) {
+	ErrorF("Restore Palette 2\n");
+	PAL_SELECT(1);
+	OUTPAL_START(0);
+	for (i = 0; i < 256; i++) {
+	    OUTREG(RADEON_PALETTE_30_DATA, restore->palette[1][i]);
+	}
     }
-
-    PAL_SELECT(0);
-    OUTPAL_START(0);
-    for (i = 0; i < 256; i++) {
-	OUTREG(RADEON_PALETTE_30_DATA, restore->palette[i]);
+    if (restore->palette_saved[0]) {
+	ErrorF("Restore Palette 1\n");
+	PAL_SELECT(0);
+	OUTPAL_START(0);
+	for (i = 0; i < 256; i++) {
+	    OUTREG(RADEON_PALETTE_30_DATA, restore->palette[0][i]);
+	}
     }
 }
 
@@ -5737,6 +5737,20 @@ RADEONSaveBIOSRegisters(ScrnInfoPtr pScrn, RADEONSavePtr save)
     }
 }
 
+void radeon_save_palette_on_demand(ScrnInfoPtr pScrn, int palID)
+{
+    RADEONInfoPtr  info       = RADEONPTR(pScrn);
+    RADEONSavePtr  save       = info->SavedReg;
+
+    if (save->palette_saved[palID] == TRUE)
+        return;
+
+    if (!IS_AVIVO_VARIANT)
+        RADEONSavePalette(pScrn, palID, save);
+
+    save->palette_saved[palID] = TRUE;
+}
+
 /* Save everything needed to restore the original VC state */
 static void RADEONSave(ScrnInfoPtr pScrn)
 {
@@ -5760,12 +5774,9 @@ static void RADEONSave(ScrnInfoPtr pScrn)
 	 * setup in the card at all !!
 	 */
 	vgaHWSave(pScrn, &hwp->SavedReg, VGA_SR_MODE); /* Save mode only */
-# elif defined(__linux__)
+# else
 	/* Save only mode * & fonts */	
 	vgaHWSave(pScrn, &hwp->SavedReg, VGA_SR_MODE | VGA_SR_FONTS );
-# else
-	/* Save mode * & fonts & cmap */
-	vgaHWSave(pScrn, &hwp->SavedReg, VGA_SR_ALL);
 # endif
 	vgaHWLock(hwp);
     }
@@ -5790,7 +5801,7 @@ static void RADEONSave(ScrnInfoPtr pScrn)
 	RADEONSaveCrtcRegisters(pScrn, save);
 	RADEONSaveFPRegisters(pScrn, save);
 	RADEONSaveDACRegisters(pScrn, save);
-	RADEONSavePalette(pScrn, save);
+	/* Palette saving is done on demand now */
 
 	if (pRADEONEnt->HasCRTC2) {
 	    RADEONSaveCrtc2Registers(pScrn, save);
@@ -5844,6 +5855,7 @@ static void RADEONRestore(ScrnInfoPtr pScrn)
 	    RADEONRestoreMemMapRegisters(pScrn, restore);
 	    RADEONRestoreCommonRegisters(pScrn, restore);
 
+	    RADEONRestorePalette(pScrn, restore);
 	    if (pRADEONEnt->HasCRTC2) {
 		RADEONRestoreCrtc2Registers(pScrn, restore);
 		RADEONRestorePLL2Registers(pScrn, restore);
@@ -5900,10 +5912,8 @@ static void RADEONRestore(ScrnInfoPtr pScrn)
 	* write VGA fonts, will find a better solution in the future
 	*/
        vgaHWRestore(pScrn, &hwp->SavedReg, VGA_SR_MODE );
-# elif defined(__linux__)
-       vgaHWRestore(pScrn, &hwp->SavedReg, VGA_SR_MODE | VGA_SR_FONTS );
 # else 
-       vgaHWRestore(pScrn, &hwp->SavedReg, VGA_SR_ALL );
+       vgaHWRestore(pScrn, &hwp->SavedReg, VGA_SR_MODE | VGA_SR_FONTS );
 # endif
        vgaHWLock(hwp);
     }
@@ -5917,7 +5927,6 @@ static void RADEONRestore(ScrnInfoPtr pScrn)
     else if (IS_AVIVO_VARIANT)
 	avivo_restore_vga_regs(pScrn, restore);
     else {
-	RADEONRestorePalette(pScrn, restore);
 	RADEONRestoreDACRegisters(pScrn, restore);
     }
 #if 0
diff --git a/src/radeon_probe.h b/src/radeon_probe.h
index 94f6d7d1..8ba7214a 100644
--- a/src/radeon_probe.h
+++ b/src/radeon_probe.h
@@ -663,8 +663,8 @@ typedef struct {
 
 				/* Pallet */
     Bool              palette_valid;
-    uint32_t          palette[256];
-    uint32_t          palette2[256];
+    Bool	      palette_saved[2];
+    uint32_t          palette[2][256];
 
     uint32_t          disp2_req_cntl1;
     uint32_t          disp2_req_cntl2;